diff --git a/src/main/kotlin/no/nav/security/mock/oauth2/http/OAuth2HttpRequest.kt b/src/main/kotlin/no/nav/security/mock/oauth2/http/OAuth2HttpRequest.kt
index 54109a16..aeb62941 100644
--- a/src/main/kotlin/no/nav/security/mock/oauth2/http/OAuth2HttpRequest.kt
+++ b/src/main/kotlin/no/nav/security/mock/oauth2/http/OAuth2HttpRequest.kt
@@ -2,6 +2,7 @@ package no.nav.security.mock.oauth2.http
 
 import com.nimbusds.oauth2.sdk.GrantType
 import com.nimbusds.oauth2.sdk.TokenRequest
+import com.nimbusds.oauth2.sdk.auth.ClientAuthenticationMethod
 import com.nimbusds.oauth2.sdk.http.HTTPRequest
 import com.nimbusds.openid.connect.sdk.AuthenticationRequest
 import no.nav.security.mock.oauth2.extensions.clientAuthentication
@@ -32,7 +33,10 @@ data class OAuth2HttpRequest(
 
     fun asTokenExchangeRequest(): TokenRequest {
         val httpRequest: HTTPRequest = this.asNimbusHTTPRequest()
-        val clientAuthentication = httpRequest.clientAuthentication().requirePrivateKeyJwt(this.url.toString(), 120)
+        var clientAuthentication = httpRequest.clientAuthentication()
+        if (clientAuthentication.method == ClientAuthenticationMethod.PRIVATE_KEY_JWT) {
+            clientAuthentication = clientAuthentication.requirePrivateKeyJwt(this.url.toString(), 120)
+        }
         val tokenExchangeGrant = TokenExchangeGrant.parse(formParameters.map)
 
         // TODO: add scope if present in request
diff --git a/src/test/kotlin/no/nav/security/mock/oauth2/e2e/TokenExchangeGrantIntegrationTest.kt b/src/test/kotlin/no/nav/security/mock/oauth2/e2e/TokenExchangeGrantIntegrationTest.kt
index 39a43abc..7016ddc5 100644
--- a/src/test/kotlin/no/nav/security/mock/oauth2/e2e/TokenExchangeGrantIntegrationTest.kt
+++ b/src/test/kotlin/no/nav/security/mock/oauth2/e2e/TokenExchangeGrantIntegrationTest.kt
@@ -87,22 +87,66 @@ class TokenExchangeGrantIntegrationTest {
         }
     }
 
+    @Test
+    fun `token request with token exchange grant and client basic auth should exchange subject_token with a new token containing many of the same claims`() {
+        withMockOAuth2Server {
+            val initialSubject = "yolo"
+            val initialToken = this.issueToken(
+                issuerId = "idprovider",
+                clientId = "initialClient",
+                tokenCallback = DefaultOAuth2TokenCallback(
+                    issuerId = "idprovider",
+                    subject = initialSubject,
+                    claims = mapOf(
+                        "claim1" to "value1",
+                        "claim2" to "value2",
+                    ),
+                ),
+            )
+
+            val issuerId = "tokenx"
+            val tokenEndpointUrl = this.tokenEndpointUrl(issuerId)
+            val targetAudienceForToken = "targetAudience"
+
+            val response: ParsedTokenResponse = client.tokenRequest(
+                url = tokenEndpointUrl,
+                basicAuth = Pair("client", "secret"),
+                parameters = mapOf(
+                    "grant_type" to TOKEN_EXCHANGE.value,
+                    "subject_token_type" to SubjectTokenType.TOKEN_TYPE_JWT,
+                    "subject_token" to initialToken.serialize(),
+                    "audience" to targetAudienceForToken,
+                ),
+            ).toTokenResponse()
+
+            response shouldBeValidFor TOKEN_EXCHANGE
+            response.scope shouldBe null
+            response.tokenType shouldBe "Bearer"
+            response.issuedTokenType shouldBe "urn:ietf:params:oauth:token-type:access_token"
+
+            response.accessToken!! should verifyWith(issuerId, this)
+
+            response.accessToken.subject shouldBe initialSubject
+            response.accessToken.audience shouldContainExactly listOf(targetAudienceForToken)
+            response.accessToken.claims["claim1"] shouldBe "value1"
+            response.accessToken.claims["claim2"] shouldBe "value2"
+        }
+    }
+
     @Test
     fun `token request without client_assertion should fail`() {
         withMockOAuth2Server {
-            val response: Response =
+            val response: Response = 
                 client.tokenRequest(
-                    url = this.tokenEndpointUrl("tokenx"),
-                    parameters =
-                        mapOf(
-                            "grant_type" to TOKEN_EXCHANGE.value,
-                            "client_id" to "myid",
-                            "client_secret" to "somesecret",
-                            "subject_token_type" to SubjectTokenType.TOKEN_TYPE_JWT,
-                            "subject_token" to "yolo",
-                            "audience" to "targetAudienceForToken",
-                        ),
-                )
+                  url = this.tokenEndpointUrl("tokenx"),
+                  parameters = 
+                    mapOf(
+                      "grant_type" to TOKEN_EXCHANGE.value,
+                      "subject_token_type" to SubjectTokenType.TOKEN_TYPE_JWT,
+                      "subject_token" to "yolo",
+                      "audience" to "targetAudienceForToken",
+                  ),
+              )
             response.code shouldBe 400
         }
     }