Federal investigators on Tuesday raided the Florida offices of Imperial Holdings Inc , a company that makes lump-sum payments on legal settlements and life insurance policies, the FBI said on Tuesday.

The agents were operating on a search warrant issued from New Hampshire, the FBI said.

The Palm Beach Post reported that FBI agents appeared to be gathering evidence inside the company's offices, and pictures on its website showed agents leaving the building.

The South Florida Business Journal said an agent leaving the building said he was working for the U.S. Treasury.

Shares of Imperial were halted for pending news at 1:42 p.m. ET and did not trade the rest of the day. The stock last changed hands at $6.32, down 2.8 percent.

The company raised $179.2 million in an initial public offering in February. The stock has lost 41 percent of its value since then.

Its largest shareholder, with a 9.5 percent stake according to Thomson Reuters data, is Pine Trading Ltd, a Bahamas-registered entity that only holds Imperial shares.

According to Imperial's annual report, Pine Trading is controlled by David Haring, who also controls other entities in partnership with Imperial Chief Executive Antony Mitchell.

Insiders have recently been buying, according to Securities and Exchange Commission filings. Director Robert Rosenberg bought 1,000 shares in August, and Chief Financial Officer Rory O'Connell bought 7,500 shares then as well. O'Connell did not own any shares before that purchase, the filing showed.

Imperial lost money every year from 2008 through 2010 but was profitable in the first six months of this year, according to its posted financial statements.

The U.S. Attorney's Office in New Hampshire declined to comment. A spokeswoman for the Florida attorney general's office could not immediately comment. Imperial executives did not return calls for comment but a spokesman said the company would be issuing a statement.

Underwriters on Imperial's IPO were led by FBR Capital Markets. FBR did not return calls for comment.

(Reporting by Clare Baldwin and Ben Berkowitz; Editing by Richard Chang, Ted Kerr, Gunna Dickson, Phil Berlowitz)