Shareholders of CVS
The deal, which has come under criticism from Calpers and some proxy advisory firms, still needs the approval of Caremark shareholders, who will vote on March 16.
CVS said more than 90% of the votes cast at a special shareholder meeting in Woonsocket, R.I., were voted in favor of the deal.
Caremark agreed to be acquired by CVS in an all-stock deal in November. Express Scripts
CVS has not raised its original stock offer, which calls for Caremark shareholders to receive 1.67 CVS shares for each Caremark share. But CVS did sweeten its bid with a special dividend of $7.50 per share, which will be paid to Caremark shareholders once the deal closes.
Express Scripts also sweetened its own bid earlier this month by offering to pay interest on the cash portion of its offer.
Express Scripts said on Thursday it is "firmly committed" to raising the cash part of its offer for Caremark if it can find more synergies. But it added that Caremark had shut it out from conducting confirmatory due diligence.
"Caremark's closed door has prevented us from learning anything more about the company that would permit Express Scripts to increase its offer," Express said in a statement.
Institutional Shareholder Services, the most influential proxy advisory firm, recommended that CVS and Caremark shareholders support the deal, but others were against it.
Calpers, the largest U.S. pension fund, voted more than 3.1 million CVS shares against the plan. Calpers also said it voted more than 2.1 million Caremark shares against the deal in that vote.
CVS shares were up 1.6% at $32.82 in afternoon trading after rising as high as $32.87 following the shareholder vote. Caremark shares were up 1.5% at $62.01, while the shares of Express Scripts rose 18 cents to $81.28.