Shares of Fair Isaac Corporation, the company behind the FICO credit score, suffered the worst single-day drop in the company's history this week after the Trump administration's top housing regulator moved to strip away its decades-long monopoly on mortgage lending decisions.

Bill Pulte, the Federal Housing Finance Agency director who oversees mortgage giants Fannie Mae and Freddie Mac, announced that the two government-backed lenders will consolidate their separate pricing matrices into a single unified grid — one that puts the rival VantageScore model on equal footing with "FICO Classic" for the first time. According to Forbes, FICO stock cratered as much as 27% in the aftermath, its steepest decline since at least 2004.

How One Post Cost Shareholders Billions

Pulte's announcement came via a post on X, and Protos reported it wiped roughly $4 billion off FICO's market capitalization almost immediately. Fannie Mae and Freddie Mac together support roughly 70% of the U.S. mortgage market, and for decades FICO was the only credit-scoring model they would accept from lenders underwriting loans that the two entities would ultimately buy or guarantee.

The new unified pricing grid eliminates a roughly 20-point scoring advantage that FICO had held over VantageScore in that process — a gap that effectively forced lenders to keep paying for FICO scores even when a competing model might have told them just as much about a borrower's risk.

THE MOVE ERASES A 20-POINT SCORING EDGE FICO HELD FOR DECADES

Rivals Pounce

VantageScore's owner, credit bureau TransUnion, moved quickly to capitalize on the opening. The company said in a statement that it will hold its standalone VantageScore 4.0 mortgage pricing at $0.99 per score through December 2028, giving lenders multi-year cost certainty as they weigh switching away from FICO — a pledge Yahoo Finance described as designed to lock in defectors before FICO can respond with its own pricing concessions.

FICO has not announced a competing pricing move, and analysts covering the stock have been split on how much of its mortgage-related revenue is actually at near-term risk, since lenders will still need time — and system changes — to adopt VantageScore at scale even with the new grid in place.

What's Next

The shakeup adds fresh uncertainty for the mortgage industry, which support functions from underwriting software to loan pricing models are built around FICO's traditional dominance. Analysts expect FICO to lobby aggressively against a broader rollout and to emphasize its long track record with lenders, while VantageScore and TransUnion push to convert the FHFA's move into a permanent shift in market share before the political winds change again.