Pressure is mounting on the House to pass a bill that would would prevent widening the scope of the alternative minimum tax and also be acceptable to the White House. Without a legislative “patch” by Dec. 31, the AMT would hit millions more Americans, including many construction firms set up as partnerships and S corporations, which are taxed at individual rates.

The House approved a bill Dec. 12 that would offset the AMT patch by raising taxes on hedge fund managers, but the White House has threatened to veto any bill that includes offsets. The AMT measure that the Senate passed Dec. 6 has no revenue-raising provisions.

Steve Hall, an American Council of Engineering Companies’ vice president, predicts the House will fold. “I think they know that they have to pass something,” he says.