Publishing firm Reader's Digest ( RDA) agreed to be acquired by a Ripplewood Holdings-led investor group in a $2.4 billion transaction. The buyout group is paying $17 a share for Reader's Digest, whose stock closed Wednesday at $15.51. After the deal was announced, the stock rose $1.29, or 8.3%, to $16.80, putting it 50 cents above its 52-week high. The total transaction value includes debt that's being assumed. The board of Reader's Digest approved the merger agreement and recommended that shareholders also support the deal. Reader's Digest said the transaction should close during the first quarter of 2007.