Putnam Investments, the US investment firm, has already lost nearly $4bn (€3.5bn) of retail investor money since being charged with fraud last week and California's two big pension funds, Calpers and Calsters, are strongly considering removing a further $1.5bn of funds from Putnam's care.

Retail investors pulled $3.9bn from Putnam's equity funds in the week up to November 5, according to AMG Data. It is one of the largest weekly losses for one fund and came as most other funds enjoyed inflows against the backdrop of a strong US stock market.