New York City Mayor Zohran Mamdani is bringing his populist bent to bear on a little-noticed merger.

Mamdani is urging New York State’s top financial regulator to block Western Union’s $500 million deal for Intermex, a money transferrer that mostly services immigrants sending remittances back to Latin America. The mayor says the merger will reduce competition and raise prices for some of the lowest-earning New Yorkers.

“This merger threatens to impose a new private tax on these same remittances, in the form of higher, supracompetitive prices that will flow directly to Western Union’s corporate coffers,” Mamdani wrote in a letter to the New York State Department of Financial Services late last month, according to a copy viewed by Semafor.

Mamdani’s efforts indicate the influence that top trustbuster and mayoral adviser Lina Khan is already wielding within New York City’s government. Khan was part of the mayor’s transition and while she doesn’t have a formal position in the administration, remains an unpaid adviser to Mamdani on his economic agenda.

The merger requires state financial regulators like DFS to approve the transfer of licenses from Intermex to Western Union. City Hall doesn’t have any official say, though Mamdani’s star turn and ability to command attention give him a soapbox from which he’s taken aim at the price of hot dogs at Yankee Stadium and said he’ll be keeping a close eye on World Cup tickets for signs of price gouging.