Barclays Global Investors exchange traded funds division iShares may need a special exemption from US regulators to continue to run indices provided by Lehman Brothers after its parent, UK-listed Barclays Bank, acquires the stricken Wall Street bank.

According to media reports, iShares runs $40 billion of ETFs based on Lehman indices. Under current US regulations, an ETF provider is barred from tracking an index owned by a group member.

US legal experts commented that iShares may have to suspend the ETFs based upon Lehman indices or to get an exemption which may require a set of Chinese walls to be erected between the operations.