Chicago Public School Teachers' Pension & Retirement Fund hired Chicago Equity Partners to run $250 million in active domestic midcap core equities, said Michael J. Nehf, executive director. The firm replaced previous midcap core managers William Blair, which ran $115 million, and Iridian Asset, which ran $110 million, Mr. Nehf said. The remaining funds came from cash. Trustees of the $10 billion plan wanted to consolidate midcap core holdings into a single mandate, he said. Trustees also were concerned about the performance of the Iridian portfolio, which had been on watch for a year, he said. Both incumbents "conveyed interest" in the open search, Mr. Nehf said. David Cohen, Iridian principal, could not be reached for comment by press time. Mercer Investment Consulting assisted.