Earlier in July, Ventana rejected Roche's offer, saying the bid undervalued the company and its prospects in the fast-growing cancer-testing market.

Caris & Co raised its price target to $28, saying the bid reaffirmed the value of Avon's international presence.

HP, which has 12 board members, responded to Xerox's decision to nominate candidates by again saying the bid undervalues the company.

Ventana rejected Roche's original offer earlier this month, saying the bid undervalued the company and its prospects in the fast-growing cancer-testing market.

Standard Life criticized Essar Global's proposal in a statement on Sunday, saying the bid would deprive small shareholders of the company's future growth value.

PharMerica has rejected a $441 million takeover bid by Omnicare, saying the bid undervalued the company and could run into regulatory hurdles.