Biogen shares drop after Morgan Stanley downgrade; rest of biotech also dragged lower

A Biogen Idec lab technician
Suzanne Kreiter | The Boston Globe | Getty Images

Biogen shares declined Thursday after Morgan Stanley's Matthew Harrison downgraded them to equal weight.

"This is not a downside call, but a timing call as we see BIIB trading with the group after appreciating post the BIVV spin and on Spinraza excitement," wrote Harrison, who lowered his 12-month price target on the stock to $305. The stock closed Wednesday at $292.64. On Thursday morning, it was down 3.75 percent.