Harbor Group International LLC announced Wednesday that it made a $4 million preferred equity investment with American Realty Capital Trust Inc. to facilitate the trust's purchase of 18 bank branches in Massachusetts.

American Realty acquired the branches directly from Rockland Trust, which occupies all of them.

It is Norfolk-based Harbor Group's second preferred equity investment with American Realty. In December, it provided $4.1 million of preferred equity for American Realty's purchase of 15 Harleysville National Bank branches in suburban Philadelphia.