Assemblyman Zohran Mamdani, the Democratic nominee for New York City mayor, widened a fund-raising advantage over his rivals on Thursday, securing another $1.9 million as the city doled out matching public funds.

Mr. Mamdani had reported a surge in small campaign donations last week. But the new funds awarded by the New York City Campaign Finance Board brought his cash total to about $6.3 million, putting him on the strongest financial footing heading into fall campaigning.

The board doled out $1.4 million in matching funds to Curtis Sliwa, the Republican nominee; $482,000 to former Gov. Andrew M. Cuomo’s third-party campaign; and about $35,000 to Jim Walden, another independent.

The numbers suggested that Mr. Cuomo, in particular, had fallen well behind Mr. Mamdani’s fund-raising pace as the former governor sprinted to get back into the race after losing June’s Democratic primary to the democratic socialist upstart.

Even after transferring $68,000 from the state campaign account he used before resigning as governor and hosting several high-dollar fund-raising events in the Hamptons, Mr. Cuomo ended Thursday with only around $1.6 million in cash on hand.

The news was worse for Mayor Eric Adams, whose third-party campaign was once again outright denied any funds under the program. (The city gives qualifying candidates an eight-to-one match of small-dollar donations.)