The market turmoil of 2007 and 2008 helped to trigger a host of lawsuits against many asset managers. Some are fighting back, and their tactics could offer a model for other firms responding to claims over subprime losses.

The one to watch is State Street, whose investment arm, State Street Global Advisors (SSgA), is a defendant in at least six pending lawsuits in the US relating to active fixed income funds that suffered deep losses in 2007.

In at least one case, State Street has filed counterclaims against the plan trustees pressing the litigation, turning many allegations around on the original plaintiffs. That case was first brought in 2007 by trustees for three pension sponsors – Unisystems, Nashua Corp and the Andover Companies – who accuse SSgA of breaching its fiduciary duties under the Employee Retirement Income Security Act (Erisa) by allegedly mismanaging certain bond funds and misrepresenting their risk. The two sides have traded volleys over State Street's counterclaims.