President Trump’s banks and accounting firms must turn over his financial records to Manhattan prosecutors, the Supreme Court ruled Thursday.

Why it matters: The ruling is a stinging loss for Trump, who has fought relentlessly to keep these records secret.

The backdrop: Manhattan prosecutor Cy Vance subpoenaed 8 years' worth of the president's tax returns as part of an investigation into hush money payments made to Stormy Daniels during the 2016 election.

• Trump challenged those subpoenas as unlawful, but the court rejected that argument, ordering financial institutions to comply with Vance's subpoenas.

What's next: Vance subpoenaed those records as part of a secret grand jury process, so he likely cannot make them public before the election.

• The Supreme Court will also rule today on separate subpoenas issued by a trio of House committees.