Pension funds have the problem of having long-dated liabilities--in this fund's case, thousands of Ontario teachers whose retirements it must fund.

FORBES: Magazine Article

It may be the case that all those assets Exxon Mobil has may indeed be liabilities in the economy of the future.

FORBES: Google's Gargantuan Valuation

Shortfalls, or "underfunded pension liabilities, " need to be made up by employers or, in the case of California, taxpayers.

WSJ: Andy Kessler: The Pension Rate-of-Return Fantasy