Exhibit 99.12 [FORM OF OPINION OF BINGHAM DANA LLP] PaineWebber Municipal Series MFS Series Trust III 51 West 52nd Street 500 Boylston Street New York, NY 10019 Boston, MA 02116 Ladies and Gentlemen: This opinion is furnished to you pursuant to...Agreement and Plan of Reorganization • December 1st, 2000 • MFS Series Trust Iii
