Kaiser Aluminum rejected the latest takeover bid.

In a letter to shareholders, Kaiser Aluminum & Chemical’s management said an investor group’s $28-per-share offer to buy the Oakland company is a last-minute attempt to win shareholder votes at the April 29 annual meeting. The group is running a slate of 11 directors against Kaiser’s 12 directors. Kaiser’s management said there is no guarantee that shareholders would receive $28 per share from the offer. The investor group has said it can run the company better than current mangement.