About $12 billion was pulled out of accounts at Bernard L. Madoff’s firm in 2008, according to several people briefed on an analysis of Mr. Madoff’s business records.

About $6 billion, or half, was taken out in just the three months before the financier was arrested in December and charged with operating an extensive Ponzi scheme, these people said.

Those figures offer a bit of hope for Mr. Madoff’s thousands of defrauded customers. Under federal law, the trustee overseeing the Madoff bankruptcy can sue to retrieve that money from the investors who withdrew it.

Indeed, the trustee, Irving H. Picard of Baker & Hostetler, filed two lawsuits on Tuesday seeking the return of a total of $6.1 billion, which he estimated had been withdrawn over the last decade.