diff --git a/src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionController.java b/src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionController.java
index 1616568d..c6bd19f9 100644
--- a/src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionController.java
+++ b/src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionController.java
@@ -6,6 +6,7 @@ import net.hostsharing.hsadminng.hs.office.generated.api.v1.api.HsOfficeCoopShar
 import net.hostsharing.hsadminng.hs.office.generated.api.v1.model.HsOfficeCoopSharesTransactionInsertResource;
 import net.hostsharing.hsadminng.hs.office.generated.api.v1.model.HsOfficeCoopSharesTransactionResource;
 import net.hostsharing.hsadminng.errors.MultiValidationException;
+import net.hostsharing.hsadminng.hs.office.membership.HsOfficeMembershipEntity;
 import net.hostsharing.hsadminng.mapper.Mapper;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.format.annotation.DateTimeFormat;
@@ -131,6 +132,7 @@ public class HsOfficeCoopSharesTransactionController implements HsOfficeCoopShar
     }
 
     final BiConsumer<HsOfficeCoopSharesTransactionInsertResource, HsOfficeCoopSharesTransactionEntity> RESOURCE_TO_ENTITY_POSTMAPPER = (resource, entity) -> {
+        entity.setMembership(mapper.fetchEntity(HsOfficeMembershipEntity.class, resource.getMembershipUuid()));
         if ( resource.getAdjustedShareTxUuid() != null ) {
             entity.setAdjustedShareTx(coopSharesTransactionRepo.findByUuid(resource.getAdjustedShareTxUuid())
                 .orElseThrow(() -> new EntityNotFoundException("ERROR: [400] adjustedShareTxUuid %s not found".formatted(resource.getAdjustedShareTxUuid()))));