Adding the 1 million-square-foot tower near Rockefeller Center to his portfolio, the acquisition is the latest of string of buys with CalSTRS, which is in a joint venture with Silverstein, funded by $2 billion of California teachers’ pension fund money.

The fund has allowed Mr. Silverstein, 76, to think about something other than his three towers-to-be at the World Trade Center site, as the purchase marks his third acquisition with CalSTRS since 2006. Last fall, the partnership bought both 99 Church Street for about $170 million, a site it intends to develop, and 575 Lexington Avenue, for which it paid $400 million.

The move also speaks to the active nature – at least recently – of Paramount CEO Albert Behler, as earlier this month, the firm agreed to buy Deutsche Bank’s building at 31 W. 52^nd Street for more than $500 million. That purchase was finalized just days after Paramount, in a joint venture with Sherwood Equities, agreed to buy S.L. Green’s Class B office building at 440 Ninth Avenue for $160 million.

Silverstein Properties declined to comment. Representatives from Paramount and Eastdil Secured, which marketed the building, did not respond to requests for comment.