Thermo Fisher Scientific, the world's largest maker of scientific instruments, is set to buy Patheon in a $5.2 billion cash deal, or $35 per share, implying a premium of about 35 percent on Patheon's Friday close.
DSM holds approximately 48.7 million shares in Patheon, making it its second largest shareholder with a 33.6 percent stake. The Dutch company said it had entered into a tender and support agreement with Thermo Fisher.
Including a control premium, DSM's stake in Patheon is worth approximately 1.5 billion euros ($1.65 billion), or about 8.50 euros per share, analysts at Jefferies estimated.
Thermo Fisher's plan to buy Patheon pushed DSM shares to an all-time high of 67.92 euros on Monday. DSM shares were up 2.64 pct at 1214 GMT.
Patheon shares jumped by nearly 34 percent to $34.80 premarket in New York.
Reporting by Wout Vergauwen; editing by David Clarke and Jason Neely