Aetna Shares Keep Sliding After Outlook Lowered

Perry also lowered his 2009 earnings per share estimate for Aetna to $3.48 from $3.83.

Analysts polled by Thomson Reuters expect, on average, 2009 earnings of $3.60. That average, posted Wednesday, represented a 20-cent drop from prior day guidance of $3.80.

"Aetna has been the best run managed care company over the past few years, in our view," Perry wrote in a Wednesday research note. "Nevertheless, we think the risk profile has increased and we see better opportunities in the shares of several other companies."

Goldman Sachs analyst Matthew Borsch said in a separate note Wednesday that further earnings outlook reductions are "a distinct possibility."

"We believe underwriting pressures from last year are still catching up with Aetna, while the book for 2009 is underpriced," he wrote.

Aetna shares started tumbling in aftermarket trading after Tuesday's announcement. By Wednesday afternoon, they were down 5.6 percent, or $1.52, at $25.75.