The Export-Import Bank is a federal agency that subsidizes U.S. exports. Ask the business lobby or the Obama administration, and they'll tell you Ex-Im is all about small business. That's not what Wall Street thinks, apparently.

Boeing stock dropped 2.3 percent starting at the opening bell today, and closed there, while the market as a whole was basically flat, closing down 0.32 percent. Bloomberg News cited market analysts who peg this drop to the loss of Eric Cantor, Ex-Im's most important defender in the House:

Boeing Co. (BA) fell the most in two months as U.S. House Majority Leader Eric Cantor’s defeat in a primary election threatens congressional reauthorization of low-cost lending that benefits the world’s largest planemaker.

Keeping alive the Export-Import Bank will be an “even more high-profile/challenging fight,” Chris Krueger, a senior policy analyst for Guggenheim Securities LLC, said today by e-mail. Boeing was the “biggest loser” besides Cantor in the Virginia Republican’s surprise loss yesterday, Krueger wrote. ...

The majority leader was upended by a Tea Party-backed challenger, David Brat, a move that may embolden more-conservative Republicans to buck party leaders. Washington-based Krueger said the bank has now been thrust into a “conservative uproar” over what critics decry as “corporate welfare.”

Sounds like free-market populism has some teeth — and it's already drawn some blood.