Premarket shares of the leading U.S. credit score provider fell 7.1% on Oct. 2, while Equifax and TransUnion declined 3.4% and 1.9% respectively. The selloff follows news that the Federal Housing Finance Agency (FHFA) is considering a new mortgage rule that would require the use of two credit bureaus, further eroding the market dominance of Fair Isaac.

This regulatory pressure compounds a severe crash for FICO on Sept. 29, when shares plunged 27% in the stock's worst single day since 1989. That drop occurred after FHFA Director Bill Pulte announced a unified pricing grid for Fannie Mae and Freddie Mac, removing a 20 point disadvantage for VantageScore borrowers and giving lenders a $0.99 alternative to FICO's $10 score. Fair Isaac is now down 64% for the year and more than 68% below its all-time high, approaching its largest drawdown since the global financial crisis.