Obama

And that's what is giving Obama an edge over Republican challenger John McCain, said William Rutherford, president of Rutherford Investment Management and former State Treasurer of Oregon.

The sentiment switch comes even as, from a policy standpoint, many Wall Streeters prefer what McCain has so far espoused. And that speaks volumes.

"I think investors are saying they think the Democrats are going to win and they want to be on the winning side," said Rutherford.

The securities industry has already contributed nearly $8 million to Obama's campaign versus just over $4 million to McCain, according to the Center for Responsive Politics. That reflects a new trend this election season. Should the pace hold up through November, it would be the first time this has happened in a presidential election since the early 1990s.