Frankfurt bankers are calling for greater protection for buyers of assets following the latest move by a hedge fund to block a public takeover.

Trident European fund, a Cayman Islands-based hedge fund, has built a 5.6% stake in Phoenix, the German tyre manufacturer, which is soon to be the subject of a €229m ($274m) unsolicited bid by Continental, its larger rival. Trident was forced to disclose its shareholding once it had passed 5%.