Unusual trading in shares of Hilton Hotels detected by the New York Stock Exchange in 2007 helped lead to the insider-trading charges made last week against billionaire investor Raj Rajaratnam and five others. It also emerged on Monday that some hedge fund investors had for years harboured concerns about Rajaratnam’s Galleon Group, according to due diligence reports disclosed to the FT. More background here, and US justice department complaints here.
