The Massachusetts Office of Campaign and Political Finance has revised its rules due to the Citizens United case. According to the OCPF website a ban on corporate independent expenditures won't stand up to judicial scrutiny thus the ban has been lifted.
On Jan. 21, the US Supreme Court issued Citizens United v. FEC. Although this case has received widespread publicity, its effect in Massachusetts, at this point, can be summarized as follows: Corporations may not make direct contributions to candidates or political committees, except for ballot question committees. Corporations may make independent expenditures to support or oppose candidates. Those independent expenditures shall be disclosed in accordance with Chapter 55, Section 18A. Click here for further information.
This ruling levels the playing field between the GOP and Dems. The Democrats have been able to use unlimited labor union funding while corporations have been unable to participate in the electoral process.