Money Markets
T-bills, repo, and commercial paper supply the short-dated, collateralized funding layer whose rates anchor everything priced above them.
Money markets are where short-dated claims trade: Treasury bills, commercial paper, certificates of deposit, and repurchase agreements. Rates here (T-bill yields, SOFR, term repo) set the risk-free baseline that longer maturities build on, so a few basis points in the money market propagate into every valuation in the system. Repo deserves special attention: it is collateralized lending that lets holders of bonds raise cash without selling, and it is the funding plumbing under dealers, hedge funds, and much derivatives margin. When repo or money funds seize up, as in 2008 and 2020, central banks step in because the entire curve above depends on this layer.