Current capital requirements for banks must be adjusted to discourage banks from becoming “too-big-to-fail,” former Fed chief Alan Greenspan said on Friday.

Financial institutions which have become too big to fail gives them a “market-distorting special competitive advantage in pricing their debt and equities,” Greenspan wrote in an opinion piece in the Financial Times.

“The solution is to have graduated regulatory capital requirements to discourage them from becoming too big and to offset their competitive advantage,” he added.