Denver Employees Retirement System is reviewing three Northern Trust index fund investments as a matter of "fiduciary prudence, following Northern Trusts acquisition of Deutsche Banks global passive businesses, said Michael P. Heitzmann, executive director. Northern Trust runs $140 million in an S&P 500 fund for the $1.5 billion pension plan; $127 million in a Lehman Government Credit fund; and $34 million in a Morgan Stanley EAFE index fund. Deutsche Bank handled all three funds prior to the acquisition, he said. The review will be finished by the end of April, he said. Callan Associates is assisting.