diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10a398072..9ea110064 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ We use [semantic versioning](http://semver.org/):
 - [fix] _agent_: With `duplicates=FAIL`, the error for a duplicate, non-identical class now names the class and how to resolve the problem.
 - [fix] _agent_, _teamscale-gradle-plugin_, _teamscale-maven-plugin_: A corrupt class file whose class name cannot be read is skipped with a warning instead of failing the coverage report.
 - [fix] _impacted-test-engine_: A test that a failing assumption aborts is reported as skipped instead of as an error.
+- [fix] _teamscale-gradle-plugin_: The default excludes now match Mockito mocks (e.g. `com.company.IFoo$MockitoMock$123`) and Guice fast classes (e.g. `com.company.Foo$$FastClassByGuice$$abc`). Previously the profiler instrumented them, and the testwise coverage report warned that it found coverage for classes that were not provided.
 
 # 39.0.0
 - [breaking] _agent_: The deprecated Docker image `cqse/teamscale-jacoco-agent` is no longer published. Use `cqse/teamscale-java-profiler` instead, which has replaced it since version 36.5.0.
diff --git a/teamscale-gradle-plugin/src/main/kotlin/com/teamscale/TeamscalePlugin.kt b/teamscale-gradle-plugin/src/main/kotlin/com/teamscale/TeamscalePlugin.kt
index ea6260885..2393c41f2 100755
--- a/teamscale-gradle-plugin/src/main/kotlin/com/teamscale/TeamscalePlugin.kt
+++ b/teamscale-gradle-plugin/src/main/kotlin/com/teamscale/TeamscalePlugin.kt
@@ -58,8 +58,8 @@ class TeamscalePlugin : Plugin<Project> {
 			"okhttp3.*",
 			"okio.*",
 			"retrofit2.*",
-			"*.MockitoMock.*",
-			"*.FastClassByGuice.*",
+			"*\$MockitoMock\$*",
+			"*\$\$FastClassByGuice\$\$*",
 			"*.ConstructorAccess"
 		)
 
diff --git a/teamscale-gradle-plugin/src/test/kotlin/com/teamscale/TeamscalePluginDefaultExcludesTest.kt b/teamscale-gradle-plugin/src/test/kotlin/com/teamscale/TeamscalePluginDefaultExcludesTest.kt
new file mode 100644
index 000000000..f0623d311
--- /dev/null
+++ b/teamscale-gradle-plugin/src/test/kotlin/com/teamscale/TeamscalePluginDefaultExcludesTest.kt
@@ -0,0 +1,41 @@
+package com.teamscale
+
+import org.assertj.core.api.Assertions.assertThat
+import org.gradle.api.tasks.testing.Test
+import org.gradle.kotlin.dsl.getByType
+import org.gradle.kotlin.dsl.named
+import org.gradle.testfixtures.ProjectBuilder
+import org.gradle.testing.jacoco.plugins.JacocoTaskExtension
+import org.jacoco.core.runtime.WildcardMatcher
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+
+/** Tests which classes the plugin's default excludes match. */
+class TeamscalePluginDefaultExcludesTest {
+
+	@ParameterizedTest
+	@ValueSource(strings = ["com/x/IFoo\$MockitoMock\$123", "com/x/Foo\$\$FastClassByGuice\$\$abc"])
+	fun `default excludes match Mockito mocks and Guice fast classes`(internalClassName: String) {
+		assertThat(isExcludedByDefault(internalClassName))
+			.`as`("The default excludes should match the generated class $internalClassName")
+			.isTrue()
+	}
+
+	@ParameterizedTest
+	@ValueSource(strings = ["com/x/Foo\$Bar", "com/x/Foo\$1"])
+	fun `default excludes do not match ordinary nested or anonymous classes`(internalClassName: String) {
+		assertThat(isExcludedByDefault(internalClassName))
+			.`as`("The default excludes should not match the ordinary nested or anonymous class $internalClassName")
+			.isFalse()
+	}
+
+	private fun isExcludedByDefault(internalClassName: String): Boolean {
+		val project = ProjectBuilder.builder().build()
+		project.pluginManager.apply(TeamscalePlugin::class.java)
+		val excludes = project.tasks.named<Test>("test").get().extensions.getByType<JacocoTaskExtension>().excludes
+
+		// JaCoCo's agent replaces the dots of each pattern with slashes and matches it against the JVM internal class name.
+		val excludesMatcher = WildcardMatcher(excludes.orEmpty().joinToString(":").replace('.', '/'))
+		return excludesMatcher.matches(internalClassName)
+	}
+}