Fair Isaac, the architect of the FICO score, plummeted 18% to $922.67 during Friday morning trading. The volatility rippled across the sector, with Equifax shares dropping 7.9% and TransUnion falling 8%. Experian saw a 4.8% retreat in over-the-counter trading as investors weighed the prospect of a fundamental shift in mortgage underwriting standards.

Pulte’s directive to Fannie Mae and Freddie Mac aims to force the adoption of the rival VantageScore model, a move intended to break the industry's grip on credit scoring. Beyond competitive shifts, the regulator accused Equifax, Experian, and TransUnion of systemic overcharging. He signaled that his office is exploring aggressive regulatory interventions to curb what he described as cartel-like behavior, explicitly rejecting industry attempts to manage the situation through standard corporate dialogue.