NEW YORK -- Morgan Stanley Dean Witter & Co., the top Wall Street investment bank that was the World Trade Center's largest tenant, said yesterday 15 employees were missing.

Morgan Stanley, which had 3,700 employees at the New York site that was demolished Tuesday in kamikaze-like attacks, said there are no confirmed deaths, but it still has to account for 15 employees.

Morgan Stanley had 25 floors in the World Trade Center, which was destroyed after two hijacked commercial planes slammed into its twin towers on Tuesday morning.

Operations previously located there will be moved to other sites in Manhattan and locations in New Jersey and Brooklyn. Morgan Stanley will be open for business when U.S. markets resume trading, chief executive officer Philip Purcell said.

U.S. bond markets reopened yesterday morning, but national stock markets were closed for the third day in a row. U.S. stock markets will open on Monday at 9:30 a.m. Eastern daylight time, according to Richard Grasso, chairman of the New York Stock Exchange.

Workers at Morgan Stanley's Discover credit card unit call centres fielded calls from people looking for or offering information on the firm's employees, it said.