diff --git a/common/changes/@microsoft/rush/rush-change-catalog-entries_2026-02-17-18-48.json b/common/changes/@microsoft/rush/rush-change-catalog-entries_2026-02-17-18-48.json
new file mode 100644
index 00000000000..19c8142e89d
--- /dev/null
+++ b/common/changes/@microsoft/rush/rush-change-catalog-entries_2026-02-17-18-48.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Add support for pnpm global catalog detection to `rush change`. Now, when a dependencyis changed in the pnpm global catalog, changelogs will be required for affected published packages.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@microsoft/rush"
+}
\ No newline at end of file
diff --git a/libraries/rush-lib/src/logic/ProjectChangeAnalyzer.ts b/libraries/rush-lib/src/logic/ProjectChangeAnalyzer.ts
index 77ded049ca3..a90db706a9c 100644
--- a/libraries/rush-lib/src/logic/ProjectChangeAnalyzer.ts
+++ b/libraries/rush-lib/src/logic/ProjectChangeAnalyzer.ts
@@ -23,6 +23,8 @@ import type { RushConfigurationProject } from '../api/RushConfigurationProject';
 import { BaseProjectShrinkwrapFile } from './base/BaseProjectShrinkwrapFile';
 import { PnpmShrinkwrapFile } from './pnpm/PnpmShrinkwrapFile';
 import { Git } from './Git';
+import { DependencySpecifier, DependencySpecifierType } from './DependencySpecifier';
+import type { IPnpmOptionsJson, PnpmOptionsConfiguration } from './pnpm/PnpmOptionsConfiguration';
 import {
   type IInputsSnapshotProjectMetadata,
   type IInputsSnapshot,
@@ -178,26 +180,42 @@ export class ProjectChangeAnalyzer {
       { concurrency: 10 }
     );
 
-    // External dependency changes are not allowed to be filtered, so add these after filtering
-    if (includeExternalDependencies) {
-      // Even though changing the installed version of a nested dependency merits a change file,
-      // ignore lockfile changes for `rush change` for the moment
+    // Detect per-subspace changes: catalog entries in pnpm-config.json and external dependency lockfiles
+    const subspaces: Iterable<Subspace> = rushConfiguration.subspacesFeatureEnabled
+      ? rushConfiguration.subspaces
+      : [rushConfiguration.defaultSubspace];
 
-      const subspaces: Iterable<Subspace> = rushConfiguration.subspacesFeatureEnabled
-        ? rushConfiguration.subspaces
-        : [rushConfiguration.defaultSubspace];
+    const variantToUse: string | undefined = includeExternalDependencies
+      ? (variant ?? (await this._rushConfiguration.getCurrentlyInstalledVariantAsync()))
+      : undefined;
 
-      const variantToUse: string | undefined =
-        variant ?? (await this._rushConfiguration.getCurrentlyInstalledVariantAsync());
+    await Async.forEachAsync(subspaces, async (subspace: Subspace) => {
+      const subspaceProjects: RushConfigurationProject[] = subspace.getProjects();
+
+      // Detect changes to pnpm catalog entries in pnpm-config.json
+      if (rushConfiguration.isPnpm) {
+        await this._detectCatalogChangesAsync(
+          subspace,
+          rushConfiguration,
+          changedFiles,
+          mergeCommit,
+          repoRoot,
+          terminal,
+          changedProjects
+        );
+      }
+
+      // External dependency changes are not allowed to be filtered, so add these after filtering
+      if (includeExternalDependencies) {
+        // Even though changing the installed version of a nested dependency merits a change file,
+        // ignore lockfile changes for `rush change` for the moment
 
-      await Async.forEachAsync(subspaces, async (subspace: Subspace) => {
         const fullShrinkwrapPath: string = subspace.getCommittedShrinkwrapFilePath(variantToUse);
 
         const relativeShrinkwrapFilePath: string = Path.convertToSlashes(
           path.relative(repoRoot, fullShrinkwrapPath)
         );
         const shrinkwrapStatus: IFileDiffStatus | undefined = changedFiles.get(relativeShrinkwrapFilePath);
-        const subspaceProjects: RushConfigurationProject[] = subspace.getProjects();
 
         if (shrinkwrapStatus) {
           if (shrinkwrapStatus.status !== 'M') {
@@ -215,7 +233,7 @@ export class ProjectChangeAnalyzer {
           }
 
           if (rushConfiguration.isPnpm) {
-            const subspaceHasNoProjects: boolean = subspace.getProjects().length === 0;
+            const subspaceHasNoProjects: boolean = subspaceProjects.length === 0;
             const currentShrinkwrap: PnpmShrinkwrapFile | undefined = PnpmShrinkwrapFile.loadFromFile(
               fullShrinkwrapPath,
               { subspaceHasNoProjects }
@@ -253,12 +271,12 @@ export class ProjectChangeAnalyzer {
                 `Lockfile has changed and lockfile content comparison is only supported for pnpm. Assuming all projects are affected.`
               );
             }
-            subspace.getProjects().forEach((project) => changedProjects.add(project));
+            subspaceProjects.forEach((project) => changedProjects.add(project));
             return;
           }
         }
-      });
-    }
+      }
+    });
 
     // Sort the set by projectRelativeFolder to avoid race conditions in the results
     const sortedChangedProjects: RushConfigurationProject[] = Array.from(changedProjects);
@@ -491,6 +509,133 @@ export class ProjectChangeAnalyzer {
       return ignoreMatcher;
     }
   }
+
+  /**
+   * Detects changes to pnpm catalog entries in a subspace's pnpm-config.json and marks
+   * affected projects as changed.
+   */
+  private async _detectCatalogChangesAsync(
+    subspace: Subspace,
+    rushConfiguration: RushConfiguration,
+    changedFiles: Map<string, IFileDiffStatus>,
+    mergeCommit: string,
+    repoRoot: string,
+    terminal: ITerminal,
+    changedProjects: Set<RushConfigurationProject>
+  ): Promise<void> {
+    const pnpmOptions: PnpmOptionsConfiguration | undefined = subspace.getPnpmOptions();
+    // Default to an empty object if no global catalogs are configured, handle case of globalCatalogs being deleted
+    const currentCatalogs: Record<string, Record<string, string>> = pnpmOptions?.globalCatalogs ?? {};
+
+    const pnpmConfigRelativePath: string = Path.convertToSlashes(
+      path.relative(repoRoot, subspace.getPnpmConfigFilePath())
+    );
+
+    if (!changedFiles.has(pnpmConfigRelativePath)) {
+      return;
+    }
+
+    // Determine which specific packages changed within each catalog namespace
+    // Maps catalogNamespace (e.g. "default", "react17") → Set of changed package names
+    let oldCatalogs: Record<string, Record<string, string>> | undefined;
+    try {
+      const oldPnpmConfigText: string = await this._git.getBlobContentAsync({
+        blobSpec: `${mergeCommit}:${pnpmConfigRelativePath}`,
+        repositoryRoot: repoRoot
+      });
+      const oldPnpmConfig: IPnpmOptionsJson = JSON.parse(oldPnpmConfigText);
+      oldCatalogs = oldPnpmConfig.globalCatalogs ?? {};
+    } catch {
+      // Old file didn't exist or was unparseable — treat all packages in all current catalogs as changed
+      if (rushConfiguration.subspacesFeatureEnabled) {
+        terminal.writeLine(
+          `"${subspace.subspaceName}" subspace pnpm-config.json was created or unparseable. Assuming all projects are affected.`
+        );
+      } else {
+        terminal.writeLine(
+          `pnpm-config.json was created or unparseable. Assuming all projects are affected.`
+        );
+      }
+    }
+
+    const changedCatalogPackages: Map<string, Set<string>> = new Map<string, Set<string>>();
+
+    if (oldCatalogs === undefined) {
+      // Could not load old catalogs — treat all packages in all current catalogs as changed
+      for (const [catalogName, packages] of Object.entries(currentCatalogs)) {
+        changedCatalogPackages.set(catalogName, new Set(Object.keys(packages)));
+      }
+    } else {
+      // Check current catalogs for new or modified package entries
+      for (const [catalogName, packages] of Object.entries(currentCatalogs)) {
+        const oldPackages: Record<string, string> | undefined = oldCatalogs[catalogName];
+        if (!oldPackages) {
+          // Entire catalog is new — all packages in it are changed
+          changedCatalogPackages.set(catalogName, new Set(Object.keys(packages)));
+          continue;
+        }
+        const changedPkgs: Set<string> = new Set<string>();
+        for (const [pkgName, version] of Object.entries(packages)) {
+          if (oldPackages[pkgName] !== version) {
+            changedPkgs.add(pkgName);
+          }
+        }
+        // Check for packages that were removed from this catalog
+        for (const pkgName of Object.keys(oldPackages)) {
+          if (!(pkgName in packages)) {
+            changedPkgs.add(pkgName);
+          }
+        }
+        if (changedPkgs.size > 0) {
+          changedCatalogPackages.set(catalogName, changedPkgs);
+        }
+      }
+
+      // Check for catalogs that were entirely removed
+      for (const [catalogName, oldPackages] of Object.entries(oldCatalogs)) {
+        if (!(catalogName in currentCatalogs)) {
+          changedCatalogPackages.set(catalogName, new Set(Object.keys(oldPackages)));
+        }
+      }
+    }
+
+    if (changedCatalogPackages.size > 0) {
+      // Check each project in the subspace to see if it depends on a changed catalog package
+      const subspaceProjects: RushConfigurationProject[] = subspace.getProjects();
+      for (const project of subspaceProjects) {
+        const { dependencies, devDependencies, optionalDependencies, peerDependencies } = project.packageJson;
+        const allDeps: Record<string, string>[] = [
+          dependencies ?? {},
+          devDependencies ?? {},
+          optionalDependencies ?? {},
+          peerDependencies ?? {}
+        ];
+
+        let isAffected: boolean = false;
+        for (const deps of allDeps) {
+          if (isAffected) {
+            break;
+          }
+          for (const [depName, depVersion] of Object.entries(deps)) {
+            const specifier: DependencySpecifier = DependencySpecifier.parseWithCache(depName, depVersion);
+            if (specifier.specifierType === DependencySpecifierType.Catalog) {
+              // versionSpecifier holds the catalog name (empty string for "catalog:")
+              const catalogName: string = specifier.versionSpecifier || 'default';
+              const changedPkgs: Set<string> | undefined = changedCatalogPackages.get(catalogName);
+              if (changedPkgs?.has(depName)) {
+                isAffected = true;
+                break;
+              }
+            }
+          }
+        }
+
+        if (isAffected) {
+          changedProjects.add(project);
+        }
+      }
+    }
+  }
 }
 
 /**
diff --git a/libraries/rush-lib/src/logic/test/ProjectChangeAnalyzer.test.ts b/libraries/rush-lib/src/logic/test/ProjectChangeAnalyzer.test.ts
index 7be396977c9..b03269fc014 100644
--- a/libraries/rush-lib/src/logic/test/ProjectChangeAnalyzer.test.ts
+++ b/libraries/rush-lib/src/logic/test/ProjectChangeAnalyzer.test.ts
@@ -583,6 +583,531 @@ describe(ProjectChangeAnalyzer.name, () => {
       });
       expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(true);
     });
+
+    describe('catalog change detection', () => {
+      function getCatalogRushConfiguration(): RushConfiguration {
+        return RushConfiguration.loadFromConfigurationFile(
+          resolve(__dirname, 'repoWithCatalogs', 'rush.json')
+        );
+      }
+
+      function mockPnpmConfigChanged(): void {
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/rush/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash', oldhash: 'oldhash', status: 'M' }
+            ]
+          ])
+        );
+      }
+
+      function mockOldCatalogs(catalogs: Record<string, Record<string, string>>): void {
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.resolve(JSON.stringify({ globalCatalogs: catalogs }));
+        });
+      }
+
+      it('detects change to default catalog', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // react version bumped in the default catalog
+        mockOldCatalogs({
+          default: { react: '^17.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'a' uses "catalog:" (default) for react (changed) and lodash
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(true);
+        // 'd' uses "catalog:" (default) for lodash only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'b' uses "catalog:tools" only — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        // 'e' uses "catalog:tools" for eslint only — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('detects change to named catalog', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // typescript version bumped in the tools catalog
+        mockOldCatalogs({
+          default: { react: '^18.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.2.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'b' uses "catalog:tools" for typescript (changed)
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(true);
+        // 'e' uses "catalog:tools" for eslint only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'a' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(false);
+        // 'd' uses "catalog:" (default) for lodash — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('no changes when catalogs are unchanged', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Old catalogs are identical to current
+        mockOldCatalogs({
+          default: { react: '^18.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        expect(changedProjects.size).toBe(0);
+      });
+
+      it('only marks projects whose specific catalog package changed, not all projects in the same catalog namespace', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Only react changed in the default catalog; lodash is unchanged
+        mockOldCatalogs({
+          default: { react: '^17.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'a' uses "catalog:" for react (changed) and lodash (unchanged) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(true);
+        // 'd' uses "catalog:" for lodash only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'b' uses "catalog:tools" for typescript — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        // 'e' uses "catalog:tools" for eslint — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('marks project when its specific package version changed in catalog, even if other packages in same catalog are unchanged', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Only lodash changed in the default catalog; react is unchanged
+        mockOldCatalogs({
+          default: { react: '^18.0.0', lodash: '^4.16.0' },
+          tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'a' uses "catalog:" for react (unchanged) and lodash (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(true);
+        // 'd' uses "catalog:" for lodash (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(true);
+        // 'b' uses "catalog:tools" for typescript — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        // 'e' uses "catalog:tools" for eslint — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('only marks projects whose specific named catalog package changed', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Only typescript changed in the tools catalog; eslint is unchanged
+        mockOldCatalogs({
+          default: { react: '^18.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.2.0', eslint: '^8.50.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'b' uses "catalog:tools" for typescript (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(true);
+        // 'e' uses "catalog:tools" for eslint only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'a' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(false);
+        // 'd' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('marks project when its specific named catalog package changed', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Only eslint changed in the tools catalog; typescript is unchanged
+        mockOldCatalogs({
+          default: { react: '^18.0.0', lodash: '^4.17.21' },
+          tools: { typescript: '~5.3.0', eslint: '^8.40.0' }
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'e' uses "catalog:tools" for eslint (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(true);
+        // 'b' uses "catalog:tools" for typescript only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        // 'a' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(false);
+        // 'd' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('all catalog-using projects marked as changed when no old catalog existed', async () => {
+        const rushConfiguration: RushConfiguration = getCatalogRushConfiguration();
+        mockPnpmConfigChanged();
+        // Old file did not exist in git
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.reject(new Error('fatal: path not found'));
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // All catalog-using projects detected: 'a' (default: react, lodash), 'b' (tools: typescript), 'd' (default: lodash), 'e' (tools: eslint)
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(true);
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(true);
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(true);
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(true);
+        // 'c' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+    });
+
+    describe('subspace catalog change detection', () => {
+      function getSubspaceCatalogRushConfiguration(): RushConfiguration {
+        return RushConfiguration.loadFromConfigurationFile(
+          resolve(__dirname, 'repoWithSubspacesCatalogs', 'rush.json')
+        );
+      }
+
+      it('detects change to default catalog in subspace', async () => {
+        const rushConfiguration: RushConfiguration = getSubspaceCatalogRushConfiguration();
+
+        // Only the subspace pnpm-config.json changed
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash', oldhash: 'oldhash', status: 'M' }
+            ]
+          ])
+        );
+
+        // foo version bumped in the default catalog
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.resolve(
+            JSON.stringify({
+              globalCatalogs: {
+                default: { foo: '~1.0.0', bar: '^3.0.0' },
+                tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+              }
+            })
+          );
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'd' uses "catalog:" (default) for foo (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(true);
+        // 'g' uses "catalog:" (default) for bar only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('g')!)).toBe(false);
+        // 'e' uses "catalog:tools" for typescript — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'h' uses "catalog:tools" for eslint — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('h')!)).toBe(false);
+        // 'f' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('f')!)).toBe(false);
+        // default subspace projects should not be affected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(false);
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+      });
+
+      it('detects change to named catalog in subspace', async () => {
+        const rushConfiguration: RushConfiguration = getSubspaceCatalogRushConfiguration();
+
+        // Only the subspace pnpm-config.json changed
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash', oldhash: 'oldhash', status: 'M' }
+            ]
+          ])
+        );
+
+        // typescript version bumped in the tools catalog
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.resolve(
+            JSON.stringify({
+              globalCatalogs: {
+                default: { foo: '~2.0.0', bar: '^3.0.0' },
+                tools: { typescript: '~5.2.0', eslint: '^8.50.0' }
+              }
+            })
+          );
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'e' uses "catalog:tools" for typescript (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(true);
+        // 'h' uses "catalog:tools" for eslint only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('h')!)).toBe(false);
+        // 'd' uses "catalog:" (default) for foo — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'g' uses "catalog:" (default) for bar — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('g')!)).toBe(false);
+        // 'f' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('f')!)).toBe(false);
+        // default subspace projects should not be affected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(false);
+      });
+
+      it('only marks subspace projects whose specific default catalog package changed', async () => {
+        const rushConfiguration: RushConfiguration = getSubspaceCatalogRushConfiguration();
+
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash', oldhash: 'oldhash', status: 'M' }
+            ]
+          ])
+        );
+
+        // Only bar changed in the default catalog; foo is unchanged
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.resolve(
+            JSON.stringify({
+              globalCatalogs: {
+                default: { foo: '~2.0.0', bar: '^2.0.0' },
+                tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+              }
+            })
+          );
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'g' uses "catalog:" for bar (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('g')!)).toBe(true);
+        // 'd' uses "catalog:" for foo only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'e' uses "catalog:tools" — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'h' uses "catalog:tools" — tools catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('h')!)).toBe(false);
+        // 'f' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('f')!)).toBe(false);
+      });
+
+      it('only marks subspace projects whose specific named catalog package changed', async () => {
+        const rushConfiguration: RushConfiguration = getSubspaceCatalogRushConfiguration();
+
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash', oldhash: 'oldhash', status: 'M' }
+            ]
+          ])
+        );
+
+        // Only eslint changed in the tools catalog; typescript is unchanged
+        mockGetBlobContentAsync.mockImplementation(() => {
+          return Promise.resolve(
+            JSON.stringify({
+              globalCatalogs: {
+                default: { foo: '~2.0.0', bar: '^3.0.0' },
+                tools: { typescript: '~5.3.0', eslint: '^8.40.0' }
+              }
+            })
+          );
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'h' uses "catalog:tools" for eslint (changed) — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('h')!)).toBe(true);
+        // 'e' uses "catalog:tools" for typescript only (unchanged) — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'd' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(false);
+        // 'g' uses "catalog:" (default) — default catalog is unchanged
+        expect(changedProjects.has(rushConfiguration.getProjectByName('g')!)).toBe(false);
+        // 'f' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('f')!)).toBe(false);
+      });
+
+      it('detects changes when multiple subspace pnpm-configs have catalog changes', async () => {
+        const rushConfiguration: RushConfiguration = getSubspaceCatalogRushConfiguration();
+
+        // Both the default subspace and named subspace pnpm-config.json files changed
+        mockGetRepoChanges.mockReturnValue(
+          new Map<string, IFileDiffStatus>([
+            [
+              'common/config/subspaces/default/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash1', oldhash: 'oldhash1', status: 'M' }
+            ],
+            [
+              'common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json',
+              { mode: 'modified', newhash: 'newhash2', oldhash: 'oldhash2', status: 'M' }
+            ]
+          ])
+        );
+
+        // Return old catalogs based on which config is being read
+        mockGetBlobContentAsync.mockImplementation((opts: { blobSpec: string; repositoryRoot: string }) => {
+          if (opts.blobSpec.includes('default/pnpm-config.json')) {
+            // react version bumped in the default subspace
+            return Promise.resolve(JSON.stringify({ globalCatalogs: { default: { react: '^17.0.0' } } }));
+          }
+          if (opts.blobSpec.includes('project-change-analyzer-test-subspace/pnpm-config.json')) {
+            // foo version bumped in the named subspace; bar, tools unchanged
+            return Promise.resolve(
+              JSON.stringify({
+                globalCatalogs: {
+                  default: { foo: '~1.0.0', bar: '^3.0.0' },
+                  tools: { typescript: '~5.3.0', eslint: '^8.50.0' }
+                }
+              })
+            );
+          }
+          return Promise.resolve('{}');
+        });
+
+        const projectChangeAnalyzer: ProjectChangeAnalyzer = new ProjectChangeAnalyzer(rushConfiguration);
+        const terminal: Terminal = new Terminal(new StringBufferTerminalProvider(true));
+
+        const changedProjects = await projectChangeAnalyzer.getChangedProjectsAsync({
+          enableFiltering: false,
+          includeExternalDependencies: false,
+          targetBranchName: 'main',
+          terminal
+        });
+
+        // 'a' uses "catalog:" (default) for react in the default subspace — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('a')!)).toBe(true);
+        // 'd' uses "catalog:" (default) for foo (changed) in the named subspace — should be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('d')!)).toBe(true);
+        // 'g' uses "catalog:" (default) for bar (unchanged) in the named subspace — should NOT be detected
+        expect(changedProjects.has(rushConfiguration.getProjectByName('g')!)).toBe(false);
+        // 'b' has no catalog deps in default subspace
+        expect(changedProjects.has(rushConfiguration.getProjectByName('b')!)).toBe(false);
+        // 'c' has no catalog deps in default subspace
+        expect(changedProjects.has(rushConfiguration.getProjectByName('c')!)).toBe(false);
+        // 'e' uses "catalog:tools" for typescript — tools catalog is unchanged in the named subspace
+        expect(changedProjects.has(rushConfiguration.getProjectByName('e')!)).toBe(false);
+        // 'h' uses "catalog:tools" for eslint — tools catalog is unchanged in the named subspace
+        expect(changedProjects.has(rushConfiguration.getProjectByName('h')!)).toBe(false);
+        // 'f' has no catalog deps
+        expect(changedProjects.has(rushConfiguration.getProjectByName('f')!)).toBe(false);
+      });
+    });
   });
 
   describe('isPackageJsonVersionOnlyChange', () => {
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/a/package.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/a/package.json
new file mode 100644
index 00000000000..26e2a7fe95d
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/a/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "a",
+  "version": "1.0.0",
+  "description": "Project A uses default catalog",
+  "dependencies": {
+    "react": "catalog:",
+    "lodash": "catalog:"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/b/package.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/b/package.json
new file mode 100644
index 00000000000..1f535dd8543
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/b/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "b",
+  "version": "1.0.0",
+  "description": "Project B depends on A and uses tools catalog",
+  "dependencies": {
+    "a": "workspace:*"
+  },
+  "devDependencies": {
+    "typescript": "catalog:tools"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/c/package.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/c/package.json
new file mode 100644
index 00000000000..ea46bdf7c6e
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/c/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "c",
+  "version": "1.0.0",
+  "description": "Project C has no catalog dependencies"
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/common/config/rush/pnpm-config.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/common/config/rush/pnpm-config.json
new file mode 100644
index 00000000000..32448ef0221
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/common/config/rush/pnpm-config.json
@@ -0,0 +1,13 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/pnpm-config.schema.json",
+  "globalCatalogs": {
+    "default": {
+      "react": "^18.0.0",
+      "lodash": "^4.17.21"
+    },
+    "tools": {
+      "typescript": "~5.3.0",
+      "eslint": "^8.50.0"
+    }
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/d/package.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/d/package.json
new file mode 100644
index 00000000000..31e197b4f81
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/d/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "d",
+  "version": "1.0.0",
+  "description": "Project D uses only lodash from default catalog",
+  "dependencies": {
+    "lodash": "catalog:"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/e/package.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/e/package.json
new file mode 100644
index 00000000000..8992f865145
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/e/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "e",
+  "version": "1.0.0",
+  "description": "Project E uses only eslint from tools catalog",
+  "devDependencies": {
+    "eslint": "catalog:tools"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithCatalogs/rush.json b/libraries/rush-lib/src/logic/test/repoWithCatalogs/rush.json
new file mode 100644
index 00000000000..848cf846c1a
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithCatalogs/rush.json
@@ -0,0 +1,27 @@
+{
+  "pnpmVersion": "9.15.0",
+  "rushVersion": "1.0.5",
+
+  "projects": [
+    {
+      "packageName": "a",
+      "projectFolder": "a"
+    },
+    {
+      "packageName": "b",
+      "projectFolder": "b"
+    },
+    {
+      "packageName": "c",
+      "projectFolder": "c"
+    },
+    {
+      "packageName": "d",
+      "projectFolder": "d"
+    },
+    {
+      "packageName": "e",
+      "projectFolder": "e"
+    }
+  ]
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/a/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/a/package.json
new file mode 100644
index 00000000000..5c102c007ba
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/a/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "a",
+  "version": "1.0.0",
+  "description": "Test package a",
+  "dependencies": {
+    "react": "catalog:"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/b/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/b/package.json
new file mode 100644
index 00000000000..3a7fdf92a46
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/b/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "b",
+  "version": "2.0.0",
+  "description": "Test package b",
+  "dependencies": {
+    "foo": "~1.0.0"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/c/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/c/package.json
new file mode 100644
index 00000000000..84d308bd6c0
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/c/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "c",
+  "version": "3.1.1",
+  "description": "Test package c",
+  "dependencies": {
+    "b": "workspace:*"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/experiments.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/experiments.json
new file mode 100644
index 00000000000..a20c6d24388
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/experiments.json
@@ -0,0 +1,3 @@
+{
+  "exemptDecoupledDependenciesBetweenSubspaces": true
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/pnpm-config.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/pnpm-config.json
new file mode 100644
index 00000000000..fdb1cb3ac59
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/pnpm-config.json
@@ -0,0 +1,4 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/pnpm-config.schema.json",
+  "useWorkspaces": true
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/subspaces.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/subspaces.json
new file mode 100644
index 00000000000..ab4e6b3a3c4
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/subspaces.json
@@ -0,0 +1,5 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/subspaces.schema.json",
+  "subspacesEnabled": true,
+  "subspaceNames": ["project-change-analyzer-test-subspace"]
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/version-policies.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/version-policies.json
new file mode 100644
index 00000000000..fe51488c706
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/rush/version-policies.json
@@ -0,0 +1 @@
+[]
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/.pnpmfile.cjs b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/.pnpmfile.cjs
new file mode 100644
index 00000000000..ee041f83a4e
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/.pnpmfile.cjs
@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = {
+  hooks: {
+    readPackage(pkgJson) {
+      return pkgJson;
+    }
+  }
+};
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/common-versions.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/common-versions.json
new file mode 100644
index 00000000000..9280fe7b96d
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/common-versions.json
@@ -0,0 +1,8 @@
+/**
+ * This configuration file specifies NPM dependency version selections that affect all projects
+ * in a Rush repo.  More documentation is available on the Rush website: https://rushjs.io
+ */
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/common-versions.schema.json",
+  "ensureConsistentVersions": true
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/pnpm-config.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/pnpm-config.json
new file mode 100644
index 00000000000..291ec697142
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/default/pnpm-config.json
@@ -0,0 +1,8 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/pnpm-config.schema.json",
+  "globalCatalogs": {
+    "default": {
+      "react": "^18.0.0"
+    }
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/.pnpmfile.cjs b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/.pnpmfile.cjs
new file mode 100644
index 00000000000..ee041f83a4e
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/.pnpmfile.cjs
@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = {
+  hooks: {
+    readPackage(pkgJson) {
+      return pkgJson;
+    }
+  }
+};
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/common-versions.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/common-versions.json
new file mode 100644
index 00000000000..9280fe7b96d
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/common-versions.json
@@ -0,0 +1,8 @@
+/**
+ * This configuration file specifies NPM dependency version selections that affect all projects
+ * in a Rush repo.  More documentation is available on the Rush website: https://rushjs.io
+ */
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/common-versions.schema.json",
+  "ensureConsistentVersions": true
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json
new file mode 100644
index 00000000000..cc0a0ac626f
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/common/config/subspaces/project-change-analyzer-test-subspace/pnpm-config.json
@@ -0,0 +1,13 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/rush/v5/pnpm-config.schema.json",
+  "globalCatalogs": {
+    "default": {
+      "foo": "~2.0.0",
+      "bar": "^3.0.0"
+    },
+    "tools": {
+      "typescript": "~5.3.0",
+      "eslint": "^8.50.0"
+    }
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/d/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/d/package.json
new file mode 100644
index 00000000000..bf308cf79f5
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/d/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "d",
+  "version": "4.1.1",
+  "description": "Test package d",
+  "dependencies": {
+    "foo": "catalog:"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/e/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/e/package.json
new file mode 100644
index 00000000000..1d6b2e26469
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/e/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "e",
+  "version": "10.10.0",
+  "description": "Test package e",
+  "dependencies": {
+    "d": "workspace:*"
+  },
+  "devDependencies": {
+    "typescript": "catalog:tools"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/f/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/f/package.json
new file mode 100644
index 00000000000..5d6ea8a762e
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/f/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "f",
+  "version": "10.10.0",
+  "description": "Test package f"
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/g/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/g/package.json
new file mode 100644
index 00000000000..42bbb7abbd7
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/g/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "g",
+  "version": "1.0.0",
+  "description": "Test package g — uses only bar from default catalog",
+  "dependencies": {
+    "bar": "catalog:"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/h/package.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/h/package.json
new file mode 100644
index 00000000000..d6cc9ac86d6
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/h/package.json
@@ -0,0 +1,8 @@
+{
+  "name": "h",
+  "version": "1.0.0",
+  "description": "Test package h — uses only eslint from tools catalog",
+  "devDependencies": {
+    "eslint": "catalog:tools"
+  }
+}
diff --git a/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/rush.json b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/rush.json
new file mode 100644
index 00000000000..4714895adf8
--- /dev/null
+++ b/libraries/rush-lib/src/logic/test/repoWithSubspacesCatalogs/rush.json
@@ -0,0 +1,44 @@
+{
+  "rushVersion": "1.0.5",
+  "pnpmVersion": "9.15.0",
+
+  "projects": [
+    {
+      "packageName": "a",
+      "projectFolder": "a"
+    },
+    {
+      "packageName": "b",
+      "projectFolder": "b"
+    },
+    {
+      "packageName": "c",
+      "projectFolder": "c"
+    },
+    {
+      "packageName": "d",
+      "projectFolder": "d",
+      "subspaceName": "project-change-analyzer-test-subspace"
+    },
+    {
+      "packageName": "e",
+      "projectFolder": "e",
+      "subspaceName": "project-change-analyzer-test-subspace"
+    },
+    {
+      "packageName": "f",
+      "projectFolder": "f",
+      "subspaceName": "project-change-analyzer-test-subspace"
+    },
+    {
+      "packageName": "g",
+      "projectFolder": "g",
+      "subspaceName": "project-change-analyzer-test-subspace"
+    },
+    {
+      "packageName": "h",
+      "projectFolder": "h",
+      "subspaceName": "project-change-analyzer-test-subspace"
+    }
+  ]
+}