California's State Controller is calling for Calpers, the huge Californian state pension fund, to review its investments in Chevron and BP over their potential participation in the sell-off of Yukos, the now bankrupt Russian oil major whose owner, Mikhail Khodorkovsky, has been jailed.

John Chiang, also a Calpers board member, said in a letter dated March 22 to the fund he was concerned about the legal risks attached to Chevron's possible participation in the Yukos auctions, which Yukos' owners have slammed as the biggest expropriation in history.