Seth Moulton is benefiting from millions of dollars in dark money political spending from anonymous donors — most likely wealthy private equity executives who have backed him throughout his political career. Here's what you need to know:

​

1. On April 15, MA Progress Action, a pro-Moulton dark money 501(c)4 nonprofit group run by longtime Moulton ally and private equity executive Todd Kanter, began running TV and digital  ads attacking Sen. Ed Markey. The Boston Globe wrote that "aside from Kanter, it’s unclear who is involved with the group, or who is bankrolling the ads...As a 501(c)(4), or a so-called social welfare organization, MA Progress Action is not required to publicly disclose the names of its donors."

2. In contrast to the pro-Markey Commonwealth Together PAC, which has filed FEC disclosures showing all money raised and spent, the pro-Moulton dark money group isn't revealing any information about its donors or spending, despite its blatant electioneering. That means voters don't know how much Seth Moulton's private equity backers are pouring into this race, or who exactly is spending potentially millions of dollars to elect him.

3. On April 23, the Campaign Legal Center, a DC-based nonpartisan voting rights & election integrity group, filed an FEC complaint alleging that MA Progress Action is violating federal independent-expenditure reporting requirements and campaign finance laws with its ad.

4. On May 14, Common Cause Massachusetts, a nonpartisan good-government watchdog organization, sent a letter urging Seth Moulton to "immediately and publicly call for 501(c)(4) groups supporting your candidacy to disclose their donors – specifically those donors that are funding their political spending – and the amounts of each contribution."

5. As of today, Moulton has refused to call on MA Progress Action to disclose its donors, giving his implicit support to a multi-million-dollar dark money spending effort on his behalf.