Washington Mutual Inc. of Seattle moved to seal its position as the largest thrift and join the ranks of the biggest banks by signing a definitive merger agreement with H.F. Ahmanson & Co.

In a startling turn by bitter rivals, Washington Mutual said Tuesday it would pay $9.9 billion in stock for the California-based parent company of the venerable Home Savings of America.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.