In a planned stock-swap "merger of equals," Biogen Inc. and IDEC Pharmaceuticals Inc. said they have entered an agreement that would create a combined entity with a market cap of $13.7 billion, the third-largest biotechnology firm based on revenue, profits and research and development spending.

Forget the "open window" metaphor. Call it financing with the top down.Convertible notes are increasingly popular this summer, with more than a dozen roaring down the cash highway so far in June. The list of issuers includes companies big and small, with the larger sales declared by such firms as Cephalon Inc., pricing $600 million in convertible notes, and ICOS Corp. aiming to raise $250 million.