Express Scripts ( ESRX ) feels that its offer for Caremark undefined is sweet enough as it is. To the surprise and disappointment of some, Express Scripts resisted upping its bid for rival pharmacy benefit manager Caremark this week and announced a backup plan instead. Express Scripts said that it will spend $1 billion on its own stock if Caremark winds up merging with the CVS ( CVS ) drugstore chain as planned. Moreover, the company indicated that it will buy its stock back rapidly, perhaps through a Dutch auction, if it winds up shifting to Plan B. For now, however, Express Scripts has excluded both possibilities from its new -- and higher -- guidance. The company boosted its 2007 outlook substantially based on the strength of its operating results. Now, Express Scripts expects to generate profits of $4.08 to $4.20 a share -- up 18 cents from an earlier forecast -- during the current year. Half of that improvement comes from rising generic utilization rates and lower drug prices.