This is part three of a multipart series on the factors that drive U.S. and foreign bond prices and yields.
[Part One is here, Part Two here, Ed.]
The yield on a bond is made up of several components. Some think of the return on a bond as the sum of the risk-free rate of interest (how impatient we are to get our money back, or how much we need to be compensated to delay consumption) and a risk premium (the additional return we require to compensate us for the risk of default, the risk the bond will be called, the risk of inflation reducing the purchase power of the repaid dollars, and many other sources of risk as outlined in the most recent article in this series).
Another useful way of thinking of the return on a bond is as the sum of the real rate of interest and the expected rate of inflation. But what is the real rate of interest? We never actually observe that rate, unless of course the inflation rate is zero and then the real rate is just the nominal rate set in the market.
It is useful, however, to think about what drives the ability of a company to generate a real rate of return to lenders, for this is essence of capitalism and risk-taking and creating economic value and growth.

A firm’s asset cash flows support the real returns to its lenders – all kinds of lenders (debt, equity, hybrid, and derivative security holders). A firm will want to borrow more, and is willing to pay a higher interest rate for those funds, the more profitable are the projects they want to undertake, or the greater the number of profitable projects. Profitability, in turn, is determined by the relationship between demand and supply: how much does society value a good or service, and how many resources does the business use in producing the good or service. As the marginal productivity or efficiency of a business goes up, it can afford to profitably fund more projects. So the core driver of the real return on bonds is the strength of the underlying economic activity of the private economy.
Or, when viewed from the investor’s side, note that an investor will purchase a bond, or lend money to a company, if they expect to earn a return sufficient to compensate them, first, for delaying consumption and, second, for bearing the various sources of risk or uncertainty associated with the bond’s cash flows or return.
By Sherry Jarrell