Medicare Part D leverages the power of market competition to deliver prescription drug coverage to seniors.

FORBES: Why Are The Democrats Attacking The Only Successful Part Of Medicare

Although competition from fixed-odds bookies limits the Tote's market power, the Tote still has a monopoly over some types of bet.

ECONOMIST: The Tote

Australia's competition watchdog has sued credit card company Visa for alleged "misuse of market power".

BBC: Visa sued by Australian competition watchdog

Claiming "clear unfair competition", Sir Richard said PPP was guilty of "a blatant abuse of market power to retain its grip on the private sector".

BBC: News | Health | Private health insurance investigated