Or to put it another way, everything it owns outside the UK has an implicit valuation in the market of more-or-less nothing - which, some would say, is bonkers.

BBC: Why break up bid for Vodafone looms

No market risk and the implicit (or even explicit) state guarantee: Pay a fixed amount now, and when Junior goes to a state college, his tuition is covered.

FORBES: College Dropout

Depending on how you look at it, the fact that Fannie and Freddie have such a big share of the market and carry an implicit government guarantee is either a big cause for concern or the only way in which the peculiarities of America's mortgage market can operate with relative safety.

ECONOMIST: Buttonwood

With this approach, because standard, long term, market investment returns are so much higher than the implicit returns paid by completely noninvested, pay-as-you-go Social Security, all workers who exercise the personal accounts would receive more in benefits through the personal accounts earning standard long term returns than the Social Security benefits they replace.

FORBES: A Personal Account Option For Social Security

Over the past few years, an implicit weak dollar policy by the Federal Reserve has stimulated enormous growth in the U.S. stock market.

FORBES: Rising Signs for the Rising Sun