Shares of my former employer, Express Scripts (ESRX), a leading pharmacy benefits manager in the U.S., are going to fall a few points this morning. Earnings reported last night were 2 cents above expectations but the momentum traders wanted more.

Express Scripts had beaten estimates by a fairly wide margin in recent periods, and bulls were undoubtedly hoping for another "beat and raise" quarter. They got the "beat", but not the "raise".

Full year guidance remained at $3.10 to $3.22 per share in earnings. ESRX rarely misses guidance, so they will be fairly conservative. They don't raise guidance often, and when they do, it's usually only once per year.

At $93 per share, the stock was trading at 30 times 2006 earnings coming into the latest report, historically an astronomical multiple for a PBM company. It's true that accretive acquisitions are boosting growth rates above competitors like Medco (MHS) and Caremark (CMX), but 30 times earnings for ESRX is too rich, in my view.

As a result, profit taking is in order, and investors have already begun that process this morning.