As the leading pharmacy benefit manager, CVS Caremark extends mail order pharmacy services, claims processing, and prescription plan design and administration on behalf of plan sponsors, which include corporations, insurance providers and the government.

FORBES: Medicare Part D Acquisition Boosts CVS Caremark

It's considering two alternatives: First, allow corporations (which include nonprofits) and unions to use their treasury funds to pay for issue ads, but require that this funding be reported to the FEC.

FORBES: Magazine Article

This is one of the most important differences between partnerships (which include most LLCs) and S corporations.

FORBES: Chief Counsel Warning -Watch the Detail on Form K-1