Biogen (NASDAQ: BIIB) made a number of key changes Thursday and that has investors thinking a takeover could be in the company's future. The speculation has shares up over 7%.

First, Biogen announced that long-time CEO, George Scangos, is stepping down. Also, major cost cuts led the company to raise 2016 non-GAAP EPS guidance to $19.70-20.00 from $18.30-18.60. In addition, the company announced a $5 billion stock repurchase plan.

Long considered a most-act suitor in the sector, today's buyback plan from Biogen, signals, according to Stifel analyst Thomas Shrader, that it is more interested in its own pipeline including aducanumab (AD), opicinumab (MS) and nusinersen (SMA with Ionis) than it is in bringing in significant outside programs.

Shrader said while Biogen called the CEO resignation a non-issue, he said it "makes any large transaction less likely – with the notable exception of the sale of Biogen itself."

BMO Capital analyst M. Ian Somaiya said the net effects of today's moves "will be a stock that trades higher as the BIIB starts to reflect an M&A premium."