The naming-rights deal involves the 5,000-seat theater, not the larger arena also under Madison Square Garden's roof, Latham said. WaMu and Madison Square Garden said in a statement that it was the first such agreement for any part of the storied midtown Manhattan venue.
The change was to take effect immediately, and work to install new signs at the theater had already begun, said Missy Latham, a spokeswoman for Seattle-based WaMu, formerly Washington Mutual. She would not disclose the financial terms and length of the agreement.
Representatives for Madison Square Garden, owned by Bethpage, N.Y.-based Cablevision Systems, did not immediately return telephone messages early Thursday.