Activist shareholder Starboard Value has acquired an interest of 1 million share of Bristol-Myers Squibb (BMS) and has held meetings with management, the US drugmaker said. BMS added that the fund has nominated several executives to its board and informed regulatory authorities of its plans to buy additional shares.

Starboard has not publicly commented on whether its intention is to block the planned $74 million takeover of biotech Celgene, which BMS said this week is on track to close in this year’s third quarter. The news agency Reuters has speculated that this may be the case.

Reuters said the fund may be gauging investor support for action against the Celgene transaction, as it is following a pattern activists frequently use to scuttle deals they don’t like.

Citing sources, the Dow Jones news agency reported earlier that Starboard is unhappy with the Bristol-Myers plans to buy Celgene, as is the drugmaker’s fifth-largest shareholder, the Dodge & Cox mutual fund.

BMS said Starboard's stake is currently only a fraction of its 1.63 billion outstanding shares. The fund acquired its shares on Jan. 31, Bristol-Myers said, the same day its board nomination window closed. As board members Starboard has nominated its own CEO and co-founder, Jeffrey Smith, as well as John Leonard, James Tyree, Steven Shulman and Janet Vergis.

The drugmaker’s as yet unscheduled annual shareholder meeting will take place after an Apr. 12 special meeting to vote on the Celgene acquisition. Analysts have told news agencies they don’t give Starboard much of a chance to torpedo the deal announced in January.