Assemblyman Zohran Mamdani, in a preview of what a Marxist mayoralty might look like, is teaming up with the Reverend Al Sharpton to threaten the heart of American finance. Their “March on Wall Street” demands to “hold Wall Street accountable for perpetuating inequality.” Reverend Sharpton warns top banks and financial firms: “Since you have benefited from Trump, we come to tell you your benefit days are numbered.”

This rhetoric, and the nascent alliance between Mr. Mamdani and Reverend Sharpton, is a reminder that the damage from the far-left candidate’s socialist agenda can’t be confined to the five boroughs, but could harm America’s broader economy, too. Mr. Mamdani was the lone mayoral candidate to join the march at Lower Manhattan. It underscores an emerging risk, were he be elected, to America’s finance industry.

At a time when questions are arising over how far Mr. Mamdani intends to adhere to the policy platform of the Democratic Socialists of America, who call for, say, decriminalizing all misdemeanor offenses, the candidate’s pairing up with Reverend Sharpton is telling. Although Mr. Mamdani insists “my platform is not the same as national D.S.A.,” his willingness to align himself with a push to malign Wall Street is unlikely to reassure moderates.

The marchers, led by Reverend Sharpton, directed their ire toward Wall Street — and top financial institutions more broadly — for purportedly having “retreated from diversity, equity and inclusion” since President Trump’s return to the White House, WABC reports. Yet Mr. Trump’s efforts to promote colorblind equality were, ironically, one of the platform planks that led voters in November to elect the president to a second term.

The vitriol on display in yesterday’s march suggests an attempt to defy the president’s attempts to foster fairness in hiring. That points, too, to the ability a Mayor Mamdani could have to pressure New York-based firms to revert to racial preferences in their own personnel decisions. Feature, say, the some $300 billion under management in New York’s employee pension funds, which could give the city, via its investment decisions, a cudgel to influence firms.

Mr. Mamdani also looks poised to impose a wave of left-leaning regulations on city businesses. There is already a bill in the city council that would expose firms to legal liability by requiring “employers to document the reason for offering a job applicant a salary amount outside the listed range,” the New York Post reports. This builds on an existing law requiring companies to disclose salary levels in help-wanted ads to close a purported gender gap.

Businesses, the Post’s dispatch adds, “are sounding the alarm” over the proposal, warning that “it will tie up firms in unnecessary red tape and additional costs when posting job notices.” Mr. Mamdani also backs a climate bill that would force costly upgrades to city buildings. One can imagine, too, Mr. Mamdani weighing punitive new taxes, or even reparations, which he has endorsed, from Wall Street firms based at New York — a danger that is national in scope.

Nor is there solace in the idea of “legal guardrails to limit what an irresponsible New York City mayor — even a crazed socialist one — can do,” a former lieutenant governor, Betsy McCaughey, reports. “That’s more a myth than a reality,” she cautions, because Albany Democrats are likely to endorse Mr. Mamdani’s moves. The curbs on the city’s powers to tax and regulate, she says, are “tissue paper under New York’s one-party, increasingly leftist rule.” 

Despite the militancy and threatening rhetoric on display during Thursday’s March on Wall Street, there’s at least one positive impression to take from the event. The demonstration gives a sense of Mr. Mamdani’s policy aspirations — and the extent of his partnership with Reverend Sharpton — in the event he accedes to Gracie Mansion. The voters of New York City, when they head to the polls in November, will be unable to say they weren’t warned.