December 17, 2009 
My response to this question…
The Express Scripts acquisition of Wellpoint’s NextRx certainly put several captive PBMs in play, but that appears to have died down. There may be small acquisitions, but the big 3 appear focused on expansion into more health services and internationally more than buying new lives.
Other opinions?
Enabling Healthy Decisions 
Sorry, I wrote the above late at night. Reverse that.
My hope is the former, but Wall Street will be pushing them to adopt the latter
The stocks of publicly held PBMs have outperformed other publicly held managed care companies in the past 5 years due to their opaque (read:highly profitable) business model.
Wall Street fund managers want more choice other than Express Scripts or Medco as a pure play or CVS/Caremark as a hybrid.
Look for a 4th large publicly held PBM to emerge in the next year or two with SXCI as the buyer with the targets being privately held mid-majors such as Argus, Medimpact, Healthtrans, and possibly Catalyst Rx as a small publicly held PBM.
SXCI historically had a transparent business model as a fee-for-service application service provider. The real question is what business model will it adopt for its growing full-service PBM business — fee for service administrative services only or benefits management reseller with opaque mark-ups and rebate retentions.
My hope is the latter…but Wall Street will be pushing them to adopt the former.