Merrill Lynch & Co. says some of its black employees and the Reverend Al Sharpton have been subjected to racist e-mails sent by someone posing as one of the company’s managers.

In a lawsuit filed in U.S. District Court in Manhattan yesterday, the world’s largest brokerage is suing a man known only as “John Doe.” It said it suspected he lives somewhere in the Midwest.

The e-mails started showing up in early-to-mid September in the e-mail accounts of various black investment brokers, the lawsuit said.

The company said the e-mails have been created using Microsoft Corp.’s “Hotmail” e-mail service and purports to be from a Merrill Lynch regional administrative manager. Merrill Lynch will seek a court order to unmask John Doe by obtaining information about the e-mail account.

Rev. Sharpton said in a telephone interview that he has received some e-mails from someone purporting to be a Merrill Lynch employee. He said he would seek to join the action.

“I salute Merrill Lynch’s lawsuit. It’s something that’s been needed because these kinds of things have gone unchecked,” Rev. Sharpton said. “It sends a signal to other bigots and copycats who would try to hide behind an e-mail address.”

The company said the e-mails have drawn complaints from some of its black employees, has cast the Merrill Lynch employee whose name has been used in a negative light, and has tarnished the company’s reputation as well. The lawsuit seeks to stop the e-mails and unspecified damages.