Calpers, the biggest pension fund in the US, has taken a 17.5% stake in Tobam, a French boutique that spun out of Lehman Brothers' European asset management operation two-and-a-half years ago, as part of its ongoing programme of investing in small fund managers it believes are set for growth.

Calpers, properly known as the California Public Employees' Retirement System, looks after $234bn of government workers' savings in the western US state. In 2000, it began an unusual investment programme combining traditional fund-management mandates with a more private-equity-style approach; when it found a small fund manager it liked, it would not only get them to manage some of its money, but would take a stake in the company too.