““To understand what that means in commonsense terms, consider a person who plans to live off the income from $1 million invested in T-bills. Suppose he retires in a given year and converts his investments into an inflation-protected annuity with a return of 4% to 5%. He will receive an annual income of $40,000 to $50,000. But now suppose he retires a few years later, when the return on the annuity has dropped to 0.5%. His annual income will now be only $5,000. Yes, the $1 million principal amount was fully insured and protected, but you can see that he cannot possibly live on the amount he will now receive. T-bills preserve principal at all times, but the income received on them can vary enormously as return on the annuity goes up or down. Had the retiree bought instead a long-maturity U.S. Treasury bond with his $1 million, his spendable income would be secure for the life of the bond, even though the price of that bond would fluctuate substantially from day to day. The same holds true for annuities: Although their market value varies from day to day, the income from an annuity is secure throughout the retiree’s life.””
