Currently and by law, income to the Social Security Trust Fund must be invested, on a daily basis, in securities guaranteed as to both principal and interest by the Federal government. All securities held by the Trust Fund are nonmarketable “special issues” of the United States Treasury. Such securities are available only to the Trust Funds. However, there is some debate as to whether the current form of the Trust Fund is national savings or an accounting fiction.
As an alternative to the status quo, economically targeted public infrastructure investment, for example, using the Social Security Trust Fund (or, at least, a portion of it) for building or revamping infrastructure may be preferable to “special issue” savings. While there is some risk involved in infrastructure (What happens if it’s built and not used? What happens if there are considerable unplanned cost overruns, or what happens if operating and maintenance expenses exceed initial expectations (tied to revenues)?), this type of investment could serve as a substitute for some taxation as well as economic stimulus in its own right.
Elements to be Considered with Respect to Investing the Social Security Trust Fund in America’s Infrastructure
 In the past, the Trust Fund has invested in marketable Treasury securities. Marketable securities are subject to the forces of the open market and may suffer a loss, or enjoy a gain, if sold before maturity.