In a note to Signum’s clients, Chairman Charles Myers and senior partner Lew Lukens said that while they were initially convinced Republicans would maintain control of the upper chamber, they have changed their minds and think Democrats are going to take it back.

“As Joe Biden’s lead over Trump in national and battleground polling has widened, several Senate races have become closer. We are changing our call and now predict the Democrats will take the Senate,” they wrote on Tuesday. The firm has a massive policy and research arm, with its leaders all having experience that ranges from working on Wall Street to government posts in Washington.

Myers was the vice chairman at investment firm Evercore before he founded Signum. He’s currently a financial supporter of Biden’s campaign for president. Lukens was a U.S. ambassador under Hillary Clinton when she was secretary of state and also worked on national security under President George W. Bush. They have offices in New York, Washington and London. 

Myers explained to CNBC that while they tell clients to expect a blue wave in November, they’re also warning them that Biden and a Democratic-led Congress will likely lead to higher corporate taxes, including for tech, pharmaceutical and energy companies.

Signum’s flip suggests that firms on Wall Street and in the financial industry could start preparing for the end of Republican control, both in the White House and Senate. Democrats currently hold a majority in the House of Representatives.

Signum says its new prediction is based on current Senate and presidential polling, as well as historical trends. Biden is ahead in most national polls, with a Real Clear Politics polling average showing Trump down by 10 points. 

The firm believes Sen. Doug Jones, D-Ala., will lose his Senate seat, but it is convinced Democrats can pick up the seats necessary to take control in the toss-up states of Arizona, Colorado and Maine, where vulnerable GOP incumbents are facing Democratic challengers. Then there are at least six other Senate races Signum argues are within reach for Democrats, including in Montana and North Carolina. 

“For us to call the Senate flipping blue, we should feel confident that at least one of these six will go blue,” the note reads.