The Samuelson formula gives the rate of return on a mature pay-as-you-go
system. In the early years of such a system, however, beneficiaries receive a
substantially higher rate of return than the formula would suggest. Consider Generation
A from the example above. That first generation in the pay-as-you-go system received
$1 in benefits but had not contributed anything to the system. Generation A’s rate of
return thus was infinite.
In a similar vein, early beneficiaries under the Social Security system in the
United States received extremely high rates of return because they received benefits
disproportionate to their contributions. They contributed for only a limited number of
years, since much of their working lives had passed before Social Security payroll
contributions began to be collected. The earliest beneficiaries under Social Security —
those born in the 1870s — enjoyed real rates of return approaching 40 percent.
This decline in rates of return from the earliest groups of beneficiaries is a feature
of any pay-as-you-go system, under which the early beneficiaries receive very high rates
of return because they contributed little during their working years. The rate of return for
subsequent beneficiaries necessarily declines. As the system matures, that decline in
rates of return may be attenuated or exacerbated by changes in productivity and labor
force growth rates.
Two other points are worth noting. First, the decision to provide benefits at the
beginning of the program to those who did not contribute over their entire lives -- to
make the system a pay-as-you-go one rather than a funded one -- may be understandable
in terms of political exigencies, but may or may not make much sense in terms of intergenerational
welfare policy. Nonetheless, that decision in almost every country of the
world has already been made. Unless we are now willing to let existing retirees or older
workers suffer because earlier generations received a super-normal rate of return, we are
forced to bear the consequences of that decision regardless of whether the pension system
is privatized. Second, and relatedly, the super-normal rates of return enjoyed by early
beneficiaries are the mirror reflection of the sub-market rate of return on the mature
system. As Geanakoplos, Mitchell, and Zeldes (1998, 1999) emphasize, the net present
value of the pay-as-you-go system across all generations is zero. If some generations
receive super-market rates of return, all other generations must therefore receive submarket
rates of return. Again, the introduction of individual accounts does not change
that conclusion.
Myth #4: Investment of public trust funds in equities has no macroeconomic effects or
welfare implications
Many analysts of pension reform believe that investing a public trust fund in
equities rather than government bonds would have no macroeconomic or social welfare
effects. The argument is simply that such diversification is merely an asset shift, and
does not change national saving. It therefore may alter asset prices or rates of return, but
not the macroeconomy. As Alan Greenspan has stated:
If social security trust funds are shifted in part, or in whole, from U.S. Treasury
securities to private debt and equity instruments, holders of those securities in the
private sector must be induced to exchange them, net, for U.S. Treasuries. If, for
example, social security funds were invested wholly in equities, presumably they
would have to be purchased from the major holders of such equities. Private
pension and insurance funds, among other holders of equities, presumably would
have to swap equities for Treasuries. But, if the social security trust funds
achieved a higher rate of return investing in equities than in lower yielding U.S.
Treasuries, private sector incomes generated by their asset portfolios, including
retirement funds, would fall by the same amount, potentially jeopardizing their
financial condition. This zero-sum result occurs because of the assumption that no
new productive saving and investment has been induced by this portfolio
reallocation process… At best, the results of this restricted form of privatization
are ambiguous. Thus, the dilemma for the social security trust funds is that a shift
to equity investments without an increase in domestic savings may not
appreciably increase the rate of return of social security trust fund assets, and to
whatever extent that it does, would likely be mirrored by a comparable decline in
the incomes of private pension and retirement funds.