Pfizer (PFE) said late Friday it is advising shareholders not to participate in Tutanota's unsolicited mini-tender offer to purchase up to 1 million shares at $32 each.

Pfizer said the offer is conditioned on its stock closing above $32 and is subject to multiple conditions, including Tutanota obtaining financing, which it does not currently have. The company added that shareholders could receive below-market value if certain conditions are waived.