Clayton, Dubilier & Rice and TPG offered to buy all of the outstanding shares of animal-health technology and services provider Covetrus Inc. for $21 a share in cash.

The private equity firms made the non-binding offer in a letter Thursday, and CD&R already holds a 24.15% stake in the company, Covetrus said Friday in a filing. The proposed deal, which represents a 16.5% premium over the May 19 close, has an equity value of about $2.9 billion, according to Bloomberg calculations.

Covetrus shares rose as much as 18% to $21.20 as of 9:38 a.m. Friday in New York after closing at $18.02 on Thursday.

Read more: BNN Bloomberg