BlackRock has announced plans to refund $600m (€384m) beyond its initial estimate to holders of auction-rate preferred shares in some of its funds, as asset managers and banks seek ways to mollify investors stuck with the shares.

BlackRock said in April that it would redeem $860m to holders of the shares in five of its taxable, fixed-income funds and about $1bn in an undisclosed number of its tax-exempt funds.