Claremont Prep has signed a 20-year lease for 200,000 square feet at 25 Broadway. The school will move middle and high school classes into the space starting in fall 2010. Claremont had originally leased space at the Sapir Organization’s 100 Church Street but backed out of the deal. Michael Koffler, CEO of Claremont’s parent company Met Schools, said the 25 Broadway space was better for Claremont. Asking rents at the building range from $38 to $40 per square foot.