Deval Patrick made it official this morning, announcing that he'll run for the Democratic Party's presidential nomination — and he also formally resigned from Bain Capital, sources say.

The state of play: He joined the firm in 2015 to launch and lead a platform focused on "social impact investing." That group, called Bain Double Impact, is in the midst of raising its second fund. Prospective investors tell Axios' Dan Primack that Patrick had assured them he wouldn't run for president in 2020, although left the door open for the 2024 race.

Bain raised around $350 million for its first Double Impact Fund, of which a little over two-thirds is deployed into 11 portfolio companies.

There have been two exits so far (IPO for SpringWorks Therapeutics and sale of Impact Fitness to Morgan Stanley).

It's unclear if Patrick's departure will impact commitments to the fund, which is said to be targeting around $600 million.

There hasn't been a formal first close yet, although there have been verbal commitments that could be revisited.

Patrick's co-managing partner Todd Cook will become sole managing partner.

A Bain spokesman declined comment.

Twitter is already ablaze with Democrats who can't understand how a "private equity guy" expects to get the nomination in 2019, let alone one from the same firm that Mitt Romney founded.

Expect rivals to scrutinize Bain Double Impact's portfolio for employee complaints, customer complaints, and anything that doesn't scream "positive social impact."

My guess is the first one to come up might be for-profit educator Penn Foster, which experienced some scandal before Bain got involved.

The bottom line: Patrick, who defended Bain Capital during Romney's presidential run, told me upon joining Bain that he wasn't worried about what the firm's brand could mean for his future political aspirations. Now he's going to put that puzzling confidence to the test.

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