Basis trades and coupon supply keep 10-year volatility in the tape

NEW YORK — Rate volatility is not waiting for a Fed surprise. It is being produced in the plumbing: large coupon auctions, dealer balance-sheet limits, and a basis-trade community that has to adjust when repo and futures disagree.

Desks said the 10-year is the battlefield because it is where duration, mortgage hedging, and foreign official flows still meet. A two-basis-point cheapening in the auction can become a ten-basis-point story in futures by the close.

Portfolio managers who bought bonds for ballast are being paid to remember that ballast can slosh. The hedge is working. It is also moving.