South Staffordshire foundation trust has acquired the mental health learning and disability directorate from Shropshire County primary care trust.
Monitor chair Bill Moyes said: 'The acquisition is another good example of an existing foundation trust utilising its freedoms to expand the services it can provide for its patients. We expect that as foundation trusts become more established they will explore opportunities like this to increase their activity'.
In April, Heart of England foundation trust became the first to exercise its independence by acquiring neighbouring Good Hope Hospital trust.
Meanwhile, Monitor has authorised two further foundation trusts. Heatherwood and Wexham Park Hospitals trust and Dorset County Hospital trust, to take the total number to 67.