Since its launch 18 months ago, few people knew that TenantWise.com existed.

"We weren't even on the map," said M. Myers Mermel, president and co-founder of the Manhattan-based online commercial property brokerage.

That all changed with the World Trade Center collapse and the displacement of hundreds of tenants in the 13.4 million-square-foot office complex and 14 surrounding buildings.

Mermel and his 10-person staff have spent the days since the terrorist attack attempting to track the exodus.

"We thought it would be helpful to everyone," said Mermel, a former real estate adviser with Morgan Stanley. He founded TenantWise in 1999 with Caroline McLain, a former real estate portfolio manager with First Nationwide Bank.

"It's not our intention to do anything to profit off this," he added. "All of the work we've done since the 11th we've done gratis."

TenantWise's staff spent the days after the collapse attempting to locate former trade center business executives who had begun working out of their homes and borrowed offices, often reaching them on cellular telephones, Mermel said.

The effort generated a plethora of publicity for the small firm. In the days after the company's first report, published Sept. 21, Mermel was quoted in the Wall Street Journal, the New York Times, Bloomberg News, Newsday and other media.

Yesterday, TenantWise said its latest survey of companies that were tenants of the World Trade Center and surrounding buildings found that many have made long-term plans to relocate outside of Lower Manhattan.