Boston Scientific ( BSK) shares slumped Monday as J.P. Morgan downgraded the medical-device maker.

Morgan cut Boston Scientific to neutral from overweight, saying Wall Street estimates for the stock are probably too high. The broker also cited increased risk from lawsuits related to its drug-coated Taxus coronary stent.

In July and August, the company announced three recalls affecting 88,200 Taxus stents and 11,000 uncoated arterial stents, a development that sent shares to a 52-week low at the time.

J.P. Morgan also said Taxus will face renewed competition from the Cypher stent made by Johnson & Johnson ( JNJ), which recently announced plans to acquire device maker Guidant ( GDT).

Boston Scientific's stent business yielded third-quarter sales of $686 million, a 405% increase over the same period last year. The Taxus drug-coated stent contributed $640 million of total stent revenue. The company has yet to report fourth-quarter results.

The broker put Boston Scientifics' 2005 EPS at $2.05 per share, compared with a consensus estimate of $2.19.

Boston Scientific shares fell $1.14, or 3.2%, to $34.41, well off their 52-week high of $46.10.