Read MoreBrat: Cantor defeat 'was basically a miracle'
Observers say that some legislation that Cantor supported is now less likely to become law.
One is immigration reform, which Goldman Sachs and other financial firms have championed to benefit their highly skilled workforce. Two others are more niche, including extending the Export-Import Bank of the United States' charter and the Terrorism Risk Insurance Act.
"I thought it was stunning ... Eric Cantor was a sensible politician," Goldman Sachs CEO Lloyd Blankfein told CNBC on Wednesday. "I hope it doesn't mean that it will be impossible from this point forward to compromise on issues like the budget, on immigration policy, or any other issues that are wracking the country."
Blankfein hinted that Cantor's potential replacement, tea party-affiliate David Brat, wouldn't be as practical.
"At the end of the day, I don't look forward to a time when every legislator goes to Washington absolutely committed to an extreme point of view and we can never resolve anything," Blankfein said. "This is not necessarily a good signal."
Read MoreBlankfein: Eric Cantor defeat "stunning"
Goldman Sachs was Cantor's third-largest financial supporter this election cycle, behind private equity giant Blackstone Group and hedge fund firm Scoggin Capital Management. There were plenty of other financial firms among Cantor's recent supporters, as shown in this chart: