But one invitee described the contents of the invitation.

“The outcome of federal and state elections has a huge impact on what the mayor can accomplish in New York City,” the invitation read, according to the person. “And this PAC is an opportunity to harness the amazing energy in the Democratic Party and help change the direction of our politics on both a local and national level.”

The invitation came from John F. Fish, the Suffolk chief executive and a prominent Boston figure who helped spearhead the city’s failed attempt to lure the 2024 Olympics. In addition to hosting the event, Mr. Fish in December donated $5,000 — the maximum contribution amount — to Mr. de Blasio’s political action committee, records show.

“Suffolk is proud to be making strides in the New York region by introducing clients to more sophisticated planning and construction technologies and delivery methods,” said a company spokesman, Sam Spokony. The company did not respond to questions about the fund-raiser.

This wasn’t Mr. Fish and his company’s first foray into national politics.

In 2017, the Federal Election Commission fined Suffolk $34,000 for donating $200,000 to a political action committee supporting Hillary Clinton, Priorities USA, while it was working as a federal contractor in West Point, N.Y. The fine was among the larger penalties meted out in connection with the 2016 presidential election, according to the commission. (Priorities USA returned the contributions in mid-2016.)

In the last two years, Mr. Fish has contributed $2.2 million to political campaigns, mostly to elect Democrats to federal office, according to federal filings.

At the same time, Suffolk has been seeking to increase its presence in New York.

Among its projects, the company recently completed construction of an apartment tower in Brooklyn Bridge Park, a development that included city-subsidized affordable housing. And the company’s website featured a panoramic aerial shot of the Brooklyn waterfront and Lower Manhattan on its main page as of Thursday.