Prudential cut its rating on Caremark (CMX) to neutral from overweight Wednesday, questioning the sweetened bid rolled out late Tuesday by prospective merger partner CVS (CVS).

CVS said Tuesday afternoon that Caremark holders will get a $2-a-share special dividend after the companies' merger closes. CVS rolled out the dividend plan after Express Scripts ( ESRX) began a tender offer for Caremark. The Express Scripts deal is valued at $25 billion in cash and stock, the CVS deal at $22 billion in stock. Last week, Caremark rejected the Express Scripts proposal, saying it lacks strategic rationale.

But on Wednesday, Prudential questioned whether the CVS deal is good for Caremark holders.

"Although we expected a new and better offer from CVS," Prudential said, "we did not expect the shareholders of the new company to pay for that offer."

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