Calpers, the biggest U.S. public pension fund, released late on Wednesday a list of 11 firms with which it has invested that did not reply to its request for information on their use of placement agents, who are at the center of a probe of New York's pension fund.

Calpers, the $200 billion California Public Employees' Retirement System, has been under fire since disclosing last year that a placement agent firm, led by one of its former board members, had made more than $58 million in fees for representing investment firms at the fund.

As a result, Calpers has been taking a harder line on placement agents or pension-fund middlemen. The fund has sought information on placement agents hired by its investment partners, along with fees paid for their services, and is supporting legislation to regulate the middlemen as lobbyists.

Under rules for lobbyists, activities of placement agents will come under heightened scrutiny.

A lengthy investigation by New York Attorney General Andrew Cuomo of his state's pension fund has been looking into how the agents have been working there behind the scenes and exploiting political connections.

The probe, and a parallel effort by the U.S. Securities and Exchange Commission, last year looked into connections between placement agents in New York and California, which drew attention to the activities of the middle-men at Calpers.

According to a Calpers statement, the following firms have not responded to its original request for information on placement agents:

* EnerTech Capital

* Fenway Partners


* Information Technology Ventures

* Markstone Capital

* Pinnacle Ventures

* Ripplewood

* TSG Capital

* Stark Investments

* AREA Property Partners

* Page Mill Advisors

A Calpers spokesman was not immediately available to say if the firms will face any consequences for not responding to the fund's request, or if the Markstone Capital in its list is Israeli venture capital firm, Markstone Capital Group LLC, which earlier this month said it would pay $18 million to settle its role in Cuomo's probe.

Also earlier this month, Wetherly Capital Group, a placement agent said it would return $1 million associated with investments by New York's pension fund to resolve its role in Cuomo's investigation.

Los Angeles-based Wetherly also agreed to exit the placement agent business.

According to Cuomo, his office has collected $120 million for New York and its $126 billion pension fund from its probe into the way placement agents used political ties under former Democratic Comptroller Alan Hevesi to win investment contracts for clients. Five people have pleaded guilty in the Cuomo's probe.

(Reporting by Jim Christie; Editing by Valerie Lee)