CVS Corp. is offering to pay more for Caremark Rx Inc.

CVS, Woonsocket, R.I., says it has increased its cash offer to $7.50 per share, from $6. The move raises the overall value of its bid to $26 billion.

CVS made its announcement a day after a rival raised the value of its bid for Caremark, Nashville, Tenn., a pharmacy benefits manager.

The competitor, Express Scripts, Maryland Heights, Mo., said it would pay interest of about 6% a year on the cash part of its offer from April 1 until the deal is closed, or until 45 days after receiving regulatory approval. Its offer for Caremark is valued at about $26.3 billion.