Countdown begins on Ligand shares

On Aug. 31, the clock will start ticking on the conversion of Ligand Pharmaceuticals Inc.'s class A common stock to class B shares.

The 60-day countdown is a result of the San Diego company's November 1992 initial public offering, one of two done at the time with special conversion features. The deals were seen as a way to entice buyers by protecting the downside for shareholders in the slow IPO market of late 1992...