diff --git a/app/Http/Controllers/BuildController.php b/app/Http/Controllers/BuildController.php
index 8a35a3fb2f..84c8762948 100644
--- a/app/Http/Controllers/BuildController.php
+++ b/app/Http/Controllers/BuildController.php
@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers;
 
+use App\Enums\BuildGroupType;
 use App\Models\Build as EloquentBuild;
 use App\Models\BuildGroup;
 use App\Models\Project;
@@ -484,6 +485,11 @@ private function restApiPost(): JsonResponse
 
         // Should we change whether or not this build is expected?
         if (request()->has('expected') && request()->has('groupid')) {
+            // The rule would also route future submissions of this build into the group.
+            if (BuildGroup::findOrFail(request()->integer('groupid'))->type !== BuildGroupType::DAILY) {
+                abort(400, 'Builds cannot be assigned to dynamic build groups.');
+            }
+
             $buildgrouprule->Expected = request()->input('expected');
             $buildgrouprule->GroupId = request()->input('groupid');
             $buildgrouprule->SetExpected();
@@ -496,9 +502,13 @@ private function restApiPost(): JsonResponse
 
             $eloquent_build = EloquentBuild::findOrFail((int) $this->build->Id);
 
-            if (BuildGroup::findOrFail((int) $newgroupid)->project()->isNot($eloquent_build->project)) {
+            $newgroup = BuildGroup::findOrFail((int) $newgroupid);
+            if ($newgroup->project()->isNot($eloquent_build->project)) {
                 abort(403, 'Requested build group is not associated with this project.');
             }
+            if ($newgroup->type !== BuildGroupType::DAILY) {
+                abort(400, 'Builds cannot be assigned to dynamic build groups.');
+            }
 
             // Remove the build from its previous group.
             $eloquent_build->buildGroups()->detach();
diff --git a/app/Http/Controllers/ExpectedBuildController.php b/app/Http/Controllers/ExpectedBuildController.php
index e319349226..b71f167483 100644
--- a/app/Http/Controllers/ExpectedBuildController.php
+++ b/app/Http/Controllers/ExpectedBuildController.php
@@ -2,6 +2,8 @@
 
 namespace App\Http\Controllers;
 
+use App\Enums\BuildGroupType;
+use App\Models\BuildGroup as EloquentBuildGroup;
 use CDash\Model\BuildGroup;
 use CDash\Model\BuildGroupRule;
 use Illuminate\Http\JsonResponse;
@@ -103,7 +105,10 @@ private static function rest_post(Request $request, int $siteid, int $buildgroup
             abort(400, 'newgroupid not specified.');
         }
 
-        $newgroupid = htmlspecialchars($request->input('newgroupid'));
+        $newgroupid = $request->integer('newgroupid');
+        if (EloquentBuildGroup::findOrFail($newgroupid)->type !== BuildGroupType::DAILY) {
+            abort(400, 'Builds cannot be assigned to dynamic build groups.');
+        }
 
         $rule = new BuildGroupRule();
         $rule->SiteId = $siteid;
diff --git a/app/cdash/app/Controller/Api/Index.php b/app/cdash/app/Controller/Api/Index.php
index a40377b97f..0b8e36a8a1 100644
--- a/app/cdash/app/Controller/Api/Index.php
+++ b/app/cdash/app/Controller/Api/Index.php
@@ -515,6 +515,7 @@ public function beginResponseForBuildGroup(BuildGroup $buildgroup): void
 
         $buildgroup_response['id'] = $buildgroup->GetId();
         $buildgroup_response['name'] = $groupname;
+        $buildgroup_response['type'] = $buildgroup->GetType();
         $buildgroup_response['linkname'] = urlencode($groupname);
         $buildgroup_response['position'] = $buildgroup->GetPosition();
 
diff --git a/app/cdash/app/Model/BuildGroup.php b/app/cdash/app/Model/BuildGroup.php
index fb9e0c9a57..9c6826663b 100644
--- a/app/cdash/app/Model/BuildGroup.php
+++ b/app/cdash/app/Model/BuildGroup.php
@@ -371,11 +371,13 @@ public function Delete(): bool
             /** @var ?EloquentBuildGroup $newGroup */
             $newGroup = $this->eloquent_model->project?->buildgroups()->where([
                 'name' => $oldbuild->type,
+                'type' => BuildGroupType::DAILY,
             ])->first();
 
             if ($newGroup === null) {
                 $newGroup = $this->eloquent_model->project?->buildgroups()->where([
                     'name' => 'Experimental',
+                    'type' => BuildGroupType::DAILY,
                 ])->first();
             }
 
@@ -410,6 +412,10 @@ public function Delete(): bool
         return true;
     }
 
+    /**
+     * Builds are only ever assigned to daily groups.  Dynamic groups compute their builds from
+     * their own rules at display time.
+     */
     public function GetGroupIdFromRule(Build $build): int
     {
         $starttime = $build->StartTime;
@@ -419,6 +425,7 @@ public function GetGroupIdFromRule(Build $build): int
         $rule_row = DB::table('build2grouprule')
             ->join('buildgroup', 'buildgroup.id', '=', 'build2grouprule.groupid')
             ->where('buildgroup.projectid', '=', $build->ProjectId)
+            ->where('buildgroup.type', '=', BuildGroupType::DAILY)
             ->where('build2grouprule.buildtype', '=', $build->Type)
             ->where('build2grouprule.siteid', '=', $build->SiteId)
             ->where('build2grouprule.buildname', '=', $build->Name)
@@ -435,6 +442,7 @@ public function GetGroupIdFromRule(Build $build): int
         $name_rule_row = DB::table('build2grouprule')
             ->join('buildgroup', 'buildgroup.id', '=', 'build2grouprule.groupid')
             ->where('buildgroup.projectid', '=', $build->ProjectId)
+            ->where('buildgroup.type', '=', BuildGroupType::DAILY)
             ->where('build2grouprule.buildtype', '=', $build->Type)
             ->where('build2grouprule.siteid', '=', -1)
             ->whereRaw('? LIKE build2grouprule.buildname', [$build->Name])
@@ -454,6 +462,7 @@ public function GetGroupIdFromRule(Build $build): int
         $default_model = EloquentBuildGroup::where([
             'name' => $build->Type,
             'projectid' => $build->ProjectId,
+            'type' => BuildGroupType::DAILY,
         ])->first();
         if ($default_model !== null) {
             return $default_model->id;
@@ -462,6 +471,7 @@ public function GetGroupIdFromRule(Build $build): int
         return EloquentBuildGroup::where([
             'name' => 'Experimental',
             'projectid' => (int) $build->ProjectId,
+            'type' => BuildGroupType::DAILY,
         ])->first()->id ?? 0;
     }
 
diff --git a/app/cdash/public/api/v1/buildgroup.php b/app/cdash/public/api/v1/buildgroup.php
index 82140982cd..645924e823 100644
--- a/app/cdash/public/api/v1/buildgroup.php
+++ b/app/cdash/public/api/v1/buildgroup.php
@@ -17,6 +17,8 @@
 
 namespace CDash\Api\v1\BuildGroup;
 
+use App\Enums\BuildGroupType;
+use App\Models\BuildGroup as EloquentBuildGroup;
 use CDash\Database;
 use CDash\Model\Build;
 use CDash\Model\BuildGroup;
@@ -197,10 +199,14 @@ function rest_post($pdo, $projectid)
     if (isset($_POST['builds'])) {
         // Move builds to a new group.
         $group = $_POST['group'];
-        if ($group['id'] < 1) {
+        $groupid = $group['id'];
+        if ($groupid < 1) {
             $error_msg = 'Please select a group for these builds';
             abort(400, $error_msg);
         }
+        if (EloquentBuildGroup::whereKey($groupid)->firstOrFail()->type !== BuildGroupType::DAILY) {
+            abort(400, 'Builds cannot be assigned to dynamic build groups.');
+        }
 
         $builds = $_POST['builds'];
         if (array_key_exists('expected', $_POST)) {
@@ -210,8 +216,6 @@ function rest_post($pdo, $projectid)
         }
 
         foreach ($builds as $buildinfo) {
-            $groupid = $group['id'];
-
             $Build = new Build();
             $Build->Id = (int) $buildinfo['id'];
             $Build->FillFromId($Build->Id);
@@ -247,6 +251,9 @@ function rest_post($pdo, $projectid)
             $error_msg = 'Please select a BuildGroup to define.';
             abort(400, $error_msg);
         }
+        if (EloquentBuildGroup::whereKey($groupid)->firstOrFail()->type !== BuildGroupType::DAILY) {
+            abort(400, 'Builds cannot be assigned to dynamic build groups.');
+        }
 
         $nameMatch = convert_wildcards($_POST['nameMatch']);
         $type = $_POST['type'];
diff --git a/app/cdash/public/api/v1/index.php b/app/cdash/public/api/v1/index.php
index 793a3c2683..2f2e297040 100644
--- a/app/cdash/public/api/v1/index.php
+++ b/app/cdash/public/api/v1/index.php
@@ -17,6 +17,7 @@
 
 namespace CDash\Api\v1\Index;
 
+use App\Enums\BuildGroupType;
 use App\Services\ProjectService;
 use CDash\Controller\Api\Index as IndexController;
 use CDash\Database;
@@ -516,8 +517,12 @@
 
 // Create a separate "all buildgroups" section of our response.
 // This is used to allow project admins to move builds between groups.
+// Builds can't be moved into dynamic groups, so only daily groups are listed.
 $response['all_buildgroups'] = [];
 foreach ($controller->buildgroupsResponse as $group) {
+    if ($group['type'] !== BuildGroupType::DAILY->value) {
+        continue;
+    }
     $response['all_buildgroups'][] = [
         'id' => $group['id'],
         'name' => $group['name'],
diff --git a/app/cdash/tests/CMakeLists.txt b/app/cdash/tests/CMakeLists.txt
index a175237008..bf705cefb4 100644
--- a/app/cdash/tests/CMakeLists.txt
+++ b/app/cdash/tests/CMakeLists.txt
@@ -333,6 +333,8 @@ add_feature_test_in_transaction(/Feature/ManageOverviewTest)
 
 add_feature_test_in_transaction(/Feature/TestOverviewTest)
 
+add_feature_test_in_transaction(/Feature/DynamicBuildGroupTest)
+
 add_feature_test_in_transaction(/Feature/Services/AuthTokenServiceTest)
 
 add_feature_test_in_transaction(/Feature/Services/ProjectServiceTest)
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index d465221ea3..b64ce5fdde 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -738,7 +738,7 @@ parameters:
 		-
 			rawMessage: 'Parameter #1 $string of function htmlspecialchars expects string, mixed given.'
 			identifier: argument.type
-			count: 3
+			count: 2
 			path: app/Http/Controllers/ExpectedBuildController.php
 
 		-
diff --git a/resources/js/angular/views/partials/build.html b/resources/js/angular/views/partials/build.html
index 4d7e2de8a4..d3bdbab3cb 100644
--- a/resources/js/angular/views/partials/build.html
+++ b/resources/js/angular/views/partials/build.html
@@ -182,7 +182,10 @@
          data-cy="build-admin-options-panel"
          style="padding: 8px 0; display: flex; flex-direction: column; gap: 8px;">
       <div style="display: flex; flex-wrap: wrap; align-items: center; gap: 8px;">
+        <!-- Expected builds belong to daily groups.  Expected-and-missing rows in dynamic groups
+             can only come from old data, so they can still be cleared. -->
         <button class="btn btn-xs"
+                ng-if="buildgroup.type != 'Latest' || build.expectedandmissing == 1"
                 ng-class="(build.expected == 1 || build.expectedandmissing == 1) ? 'btn-warning' : 'btn-success'"
                 ng-click="toggleExpected(build, buildgroup.id)"
                 ng-disabled="build.expectedLoading"
diff --git a/resources/js/angular/views/partials/buildgroup.html b/resources/js/angular/views/partials/buildgroup.html
index d7c92aefe6..035aff1838 100644
--- a/resources/js/angular/views/partials/buildgroup.html
+++ b/resources/js/angular/views/partials/buildgroup.html
@@ -51,10 +51,11 @@ <h3 class="buildgroupname" style="display: flex; align-items: center; justify-co
     </div>
     
     <div style="display: flex; align-items: center; gap: 8px;">
-      <button class="btn btn-sm btn-success" ng-click="bulkMarkAsExpected(buildgroup, 1)" data-cy="bulk-mark-expected-btn">
+      <!-- Expected builds belong to daily groups. -->
+      <button class="btn btn-sm btn-success" ng-if="buildgroup.type != 'Latest'" ng-click="bulkMarkAsExpected(buildgroup, 1)" data-cy="bulk-mark-expected-btn">
         <span class="glyphicon glyphicon-ok"></span> Mark as Expected
       </button>
-      <button class="btn btn-sm btn-warning" ng-click="bulkMarkAsExpected(buildgroup, 0)" data-cy="bulk-mark-not-expected-btn">
+      <button class="btn btn-sm btn-warning" ng-if="buildgroup.type != 'Latest'" ng-click="bulkMarkAsExpected(buildgroup, 0)" data-cy="bulk-mark-not-expected-btn">
         <span class="glyphicon glyphicon-remove"></span> Mark as Not Expected
       </button>
       <button class="btn btn-sm btn-danger" ng-click="bulkDeleteBuilds(buildgroup)" data-cy="bulk-delete-btn">
diff --git a/tests/Feature/BuildGroupRuleTest.php b/tests/Feature/BuildGroupRuleTest.php
index 967c2ba327..84f763182d 100644
--- a/tests/Feature/BuildGroupRuleTest.php
+++ b/tests/Feature/BuildGroupRuleTest.php
@@ -75,13 +75,13 @@ private function getDashboardBuildNames(string $group_name, string $date, bool $
         return [];
     }
 
-    private function getGroupIdForNewBuild(string $name, string $starttime): int
+    private function getGroupIdForNewBuild(string $name, string $starttime, string $type = 'Nightly'): int
     {
         $build = new LegacyBuild();
         $build->ProjectId = $this->project->id;
         $build->SiteId = $this->site->id;
         $build->Name = $name;
-        $build->Type = 'Nightly';
+        $build->Type = $type;
         $build->StartTime = $starttime;
         return (new LegacyBuildGroup())->GetGroupIdFromRule($build);
     }
@@ -143,6 +143,27 @@ public function testWildcardRulesAssignNewBuildsWhileActive(): void
         self::assertSame($this->nightly->id, $this->getGroupIdForNewBuild('gcc-ended-debug', '2025-01-15 12:00:00'));
     }
 
+    public function testRulesOnDynamicGroupsDoNotAssignNewBuilds(): void
+    {
+        $latest = BuildGroup::factory()->for($this->project)->create(['type' => BuildGroupType::LATEST]);
+        $this->createRule($latest, ['buildname' => 'explicit']);
+        $this->createRule($latest, ['buildname' => '%wildcard%', 'siteid' => -1]);
+
+        self::assertSame($this->nightly->id, $this->getGroupIdForNewBuild('explicit', '2025-01-15 12:00:00'));
+        self::assertSame($this->nightly->id, $this->getGroupIdForNewBuild('gcc-wildcard-debug', '2025-01-15 12:00:00'));
+    }
+
+    public function testDynamicGroupNamedAfterBuildTypeIsNotTheDefault(): void
+    {
+        BuildGroup::factory()->for($this->project)->create([
+            'name' => 'Custom',
+            'type' => BuildGroupType::LATEST,
+        ]);
+        $experimental = $this->project->buildgroups()->where('name', 'Experimental')->firstOrFail();
+
+        self::assertSame($experimental->id, $this->getGroupIdForNewBuild('custom', '2025-01-15 12:00:00', 'Custom'));
+    }
+
     public function testChangingGroupMovesOnlyTheActiveRule(): void
     {
         $active = $this->createRule($this->nightly, ['buildname' => 'moved', 'expected' => 1]);
diff --git a/tests/Feature/DynamicBuildGroupTest.php b/tests/Feature/DynamicBuildGroupTest.php
new file mode 100644
index 0000000000..5e4ad6bfd1
--- /dev/null
+++ b/tests/Feature/DynamicBuildGroupTest.php
@@ -0,0 +1,207 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Enums\BuildGroupType;
+use App\Models\Build;
+use App\Models\BuildGroup;
+use App\Models\Project;
+use App\Models\Site;
+use App\Models\User;
+use CDash\Model\BuildGroup as LegacyBuildGroup;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+use Illuminate\Support\Carbon;
+use Illuminate\Support\Str;
+use Illuminate\Testing\TestResponse;
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\Attributes\RunInSeparateProcess;
+use Symfony\Component\HttpFoundation\Response;
+use Tests\TestCase;
+use Tests\Traits\CreatesProjects;
+
+/**
+ * Builds are only ever assigned to daily groups.  Dynamic groups compute their builds from their
+ * rules when the dashboard is shown.
+ */
+class DynamicBuildGroupTest extends TestCase
+{
+    use CreatesProjects;
+    use DatabaseTransactions;
+
+    private Project $project;
+    private User $admin;
+    private Site $site;
+    private BuildGroup $nightly;
+    private BuildGroup $latest;
+    private Build $build;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->project = $this->makePublicProject();
+        $this->admin = User::factory()->adminUser()->create();
+        $this->site = Site::factory()->create();
+        $this->nightly = $this->project->buildgroups()->where('name', 'Nightly')->firstOrFail();
+
+        $this->latest = BuildGroup::factory()->for($this->project)->create(['type' => BuildGroupType::LATEST]);
+        $this->latest->positions()->create([
+            'position' => 4,
+            'starttime' => Carbon::create(1980),
+            'endtime' => Carbon::create(1980),
+        ]);
+
+        $this->build = $this->project->builds()->create([
+            'name' => Str::uuid()->toString(),
+            'uuid' => Str::uuid()->toString(),
+            'siteid' => $this->site->id,
+            'type' => 'Nightly',
+            'starttime' => '2025-01-15 12:00:00',
+        ]);
+        $this->build->buildGroups()->attach($this->nightly);
+    }
+
+    protected function tearDown(): void
+    {
+        $_GET = $_POST = $_REQUEST = [];
+        unset($_SERVER['REQUEST_METHOD']);
+
+        parent::tearDown();
+    }
+
+    private function assertNothingAssignedToDynamicGroup(): void
+    {
+        self::assertTrue($this->nightly->builds()->whereKey($this->build->id)->exists());
+        self::assertSame(0, $this->latest->builds()->count());
+        self::assertSame(0, $this->latest->rules()->count());
+    }
+
+    /**
+     * @param array<string,mixed> $data
+     *
+     * @return TestResponse<Response>
+     */
+    private function postToLegacyBuildGroupApi(array $data): TestResponse
+    {
+        // The legacy API reads its parameters directly from the superglobals.
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_POST = $data;
+        $_REQUEST = ['projectid' => $this->project->id] + $data;
+        return $this->actingAs($this->admin)->post('/api/v1/buildgroup.php');
+    }
+
+    public function testCannotMoveBuildIntoDynamicGroup(): void
+    {
+        $this->actingAs($this->admin)->postJson('/api/v1/build.php', [
+            'buildid' => $this->build->id,
+            'expected' => 0,
+            'newgroupid' => $this->latest->id,
+        ])->assertBadRequest();
+
+        $this->assertNothingAssignedToDynamicGroup();
+    }
+
+    public function testCannotMarkBuildAsExpectedInDynamicGroup(): void
+    {
+        $this->actingAs($this->admin)->postJson('/api/v1/build.php', [
+            'buildid' => $this->build->id,
+            'expected' => 1,
+            'groupid' => $this->latest->id,
+        ])->assertBadRequest();
+
+        $this->assertNothingAssignedToDynamicGroup();
+    }
+
+    public function testCannotMoveExpectedBuildIntoDynamicGroup(): void
+    {
+        $rule = $this->nightly->rules()->create([
+            'buildtype' => 'Nightly',
+            'buildname' => $this->build->name,
+            'siteid' => $this->site->id,
+            'expected' => 1,
+            'starttime' => Carbon::create(1980),
+        ]);
+
+        $this->actingAs($this->admin)->postJson('/api/v1/expectedbuild.php', [
+            'siteid' => $this->site->id,
+            'groupid' => $this->nightly->id,
+            'name' => $this->build->name,
+            'type' => 'Nightly',
+            'newgroupid' => $this->latest->id,
+        ])->assertBadRequest();
+
+        self::assertSame($this->nightly->id, $rule->refresh()->groupid);
+        $this->assertNothingAssignedToDynamicGroup();
+    }
+
+    // buildgroup.php declares functions, so it can only be loaded once per process.
+    #[RunInSeparateProcess]
+    #[PreserveGlobalState(false)]
+    public function testCannotMoveBuildsIntoDynamicGroupFromManagePage(): void
+    {
+        $this->postToLegacyBuildGroupApi([
+            'builds' => [['id' => $this->build->id]],
+            'group' => ['id' => $this->latest->id],
+        ])->assertBadRequest();
+
+        $this->assertNothingAssignedToDynamicGroup();
+    }
+
+    #[RunInSeparateProcess]
+    #[PreserveGlobalState(false)]
+    public function testCannotDefineWildcardRuleForDynamicGroup(): void
+    {
+        $this->postToLegacyBuildGroupApi([
+            'group' => ['id' => $this->latest->id],
+            'nameMatch' => $this->build->name,
+            'type' => 'Nightly',
+        ])->assertBadRequest();
+
+        $this->assertNothingAssignedToDynamicGroup();
+    }
+
+    public function testDeletingGroupDoesNotMoveItsBuildsIntoDynamicGroup(): void
+    {
+        // The deleted group's builds go to the group named after their type, if there is one.
+        $this->latest->update(['name' => 'Custom']);
+        $custom_group = BuildGroup::factory()->for($this->project)->create();
+        $custom_build = $this->project->builds()->create([
+            'name' => Str::uuid()->toString(),
+            'uuid' => Str::uuid()->toString(),
+            'siteid' => $this->site->id,
+            'type' => 'Custom',
+        ]);
+        $custom_build->buildGroups()->attach($custom_group);
+
+        $legacy_group = new LegacyBuildGroup();
+        $legacy_group->SetId($custom_group->id);
+        self::assertTrue($legacy_group->Delete());
+
+        $experimental = $this->project->buildgroups()->where('name', 'Experimental')->firstOrFail();
+        self::assertSame([$experimental->id], $custom_build->buildGroups()->pluck('buildgroup.id')->all());
+    }
+
+    public function testDashboardOnlyOffersDailyGroupsAsMoveTargets(): void
+    {
+        // Also show the build in the dynamic group.
+        $this->latest->rules()->create([
+            'buildtype' => '',
+            'buildname' => $this->build->name,
+            'siteid' => 0,
+            'starttime' => Carbon::create(1980),
+        ]);
+
+        // The legacy API reads its parameters directly from the superglobals.
+        $_GET = $_REQUEST = ['project' => $this->project->name, 'date' => '2025-01-15'];
+        $response = $this->get('/api/v1/index.php')->assertOk();
+
+        self::assertEqualsCanonicalizing(
+            ['Nightly', 'Continuous', 'Experimental'],
+            $response->collect('all_buildgroups')->pluck('name')->all(),
+        );
+        self::assertEquals(
+            ['Nightly' => 'Daily', $this->latest->name => 'Latest'],
+            $response->collect('buildgroups')->pluck('type', 'name')->all(),
+        );
+    }
+}