San Francisco, California - The city of San Francisco has sued President Donald Trump's media company, which owns the Truth Social network, accusing it of enabling insider trading by selling Wall Street traders priority access to his posts.

City Attorney David Chiu filed the complaint on Monday in a San Francisco court against Trump Media & Technology Group (TMTG), which is 41% owned by Trump.

The suit targets Truth API, a product launched this summer.

The paid feed, costing up to $100,000 a month, lets subscribers see posts from Trump, Vice President JD Vance, and other influential accounts a fraction of a second before the general public.

Donald Trump Republican senator demands probe into Donald Trump Jr.'s Russian-funded wedding: "It's corruption"

That head start gives algorithmic trading firms an edge in analyzing announcements that could move markets.

Since the start of the war with Iran, for example, oil prices have reacted sharply to some of the president's statements on Truth Social.

"It is corruption, plain and simple," Chiu said in a statement.

"Californians should not be forced to compete against wealthy trading firms buying early access to market-moving information," he added.

The city is invoking California's unfair competition law, arguing that residents whose money is invested in pension funds are put at a disadvantage.

Trump Media spokesperson Shannon Devine responded in a statement quoted by US media: "The People of California should outsource their future lawsuits to AI chatbots who, unlike the left-wing activists masquerading as attorneys who filed this lawsuit, will grasp the basic distinction between public and nonpublic information."

In August, two US media organizations, The Intercept and the Freedom of the Press Foundation, challenged the Truth API service in federal court in New York.