At events hosted by some of Trump's Wall Street allies , it has become increasingly uncommon to find finance chairs and co-chairs from previous presidential campaigns, that source said.

"Folks have definitely checked out," said another Wall Streeter who has access to the campaign finance circuit in New York.

It's not the Fed, or regulators, or the industry's least-favorite senators who chide bankers and hedge fund execs from time to time. It's Donald Trump. One finance exec who asked not to be identified and who previously was a staunch supporter of Trump's candidacy described bankers, point blank, as really angry. He's not alone.

The Trump campaign did not respond to multiple requests for comment.

It isn't any one thing about the Trump campaign that seems to have irked the supporters he needs most. One Wall Street GOPer was critical of the overall message relayed at the Republican National Convention.

A hedge fund investor suggested that Trump's pitch to reinstate Glass-Steagall, a set of bank regulations that would potentially crimp business practices on which Wall Street has become dependent, was a curveball to his finance sector supporters.

The investor said Trump's pitch Monday to rearrange the corporate tax structure was also a surprise. Although the Republican National Convention is over, Trump continues to surprise Wall Street. Earlier Tuesday, he called the stock market a "big bubble," reiterating prior comments he has made about U.S. shares.

It remains to be seen whether Trump's policy declarations will hobble his White House ambitions. His July fundraising haul was sufficient to keep him on Clinton's heels, although Clinton still commands a cash lead.

As of the end of July, Trump's campaign had $37 million in cash on hand, compared with Clinton's $58 million. And while Trump has had success fundraising outside of Wall Street, including with a cadre of successful real estate investors including Thomas Barrack or Donald Bren, recent reports suggested that both candidates were disappointed with their Silicon Valley fundraising haul.