These are the halcyon days of cash. Money-market funds and Treasury bills offer yields around 5% with virtually no credit or interest-rate risk. Longer-term Treasuries yield less than short-term ones, a condition known as an inverted yield curve, so there is no immediate upside for venturing into later maturities. Plus, yield-curve inversion is a remarkably prescient harbinger of a future recession, making corporate bonds unappealing.