Shares in Countrywide Financial Corp. dropped more than 6 percent Monday after the troubled firm was downgraded by Keefe, Bruyette & Woods after announcing it was laying off some of its sales force.

Shares in the Calabasas-based lender were downgraded by analyst Frederick Cannon to “underperform” because a liquidity crisis had spread to the company’s bank deposits, he wrote in a report released Monday.

“There appears to be a meaningful flow of depositors to the Countrywide Bank offices to either withdraw funds or to be reassured,” Cannon said.

The downgrade came after the nation’s largest home mortgage lender said it was going to begin cutting jobs in the company’s Full Spectrum Lending unit, which focuses primarily on lending to below-prime borrowers.

Employees of the Countrywide division were notified by e-mail late Friday, news reports said. No official numbers of those affected by the layoffs were made available.

Full Spectrum has more than 18,000 employees, of which about 7,000 are sales people, Countrywide said in an SEC filing earlier this year.

Shares in Countrywide lost $4.46, or 6.8 percent, to $19.97 in afternoon trading Monday on the New York Stock Exchange. Shares have lost 24 percent in the past week and more than 40 percent over the past month.