Definition
Treasury bills maturing within one year as a percentage of total marketable US Treasury debt outstanding.
A rising bills share shifts more Treasury financing toward the short end. That raises near-term rollover needs and the amount of supply money-market funds must absorb, while making federal borrowing costs more sensitive to short rates. The series comes from the Treasury’s monthly public-debt statement, so it describes issuance structure with a publication lag; it is not a live funding-stress gauge. Liquidity Lens shows its six-month direction as forward-looking Structure context only, never as a score input.