On-the-Run versus Off-the-Run Treasuries

The most recently auctioned Treasury bond of a given maturity—the on-the-run issue—typically trades at a slight price premium over older Treasury bonds of the same maturity—the off-the-run bonds. This “roll premium” is pure liquidity: traders and banks prefer on-the-run issues because they are easier to buy and sell in size without moving the market. Bid-ask spreads are tighter, and the secondary market is deeper.

Why on-the-run matters

The U.S. Treasury Department auctions bonds across a range of maturities—2-year, 5-year, 10-year, 30-year, and others. Each maturity is auctioned regularly (e.g., the 10-year every month, the 2-year every week). Each new auction produces a fresh issue.

Within minutes of settlement, the new issue becomes the on-the-run benchmark. The Federal Reserve, financial reporters, and traders reference the on-the-run yield when quoting “the” 10-year Treasury yield. Market participants use on-the-run bonds as the standard against which all other fixed-income securities are priced.

This concentration of attention and trading creates liquidity. Dealers maintain tight bid-ask spreads on on-the-run bonds (often just 1 basis point or less) because they trade in enormous volume. The secondary market is deep—you can buy or sell millions of dollars in seconds without a material price concession.

When a new issue is auctioned and replaces the old one, the previous on-the-run bond becomes off-the-run. It is still an identical security with the same coupon, maturity, and credit quality, but trading moves to the on-the-run issue. The off-the-run bond now trades with wider spreads and thinner volume.

The liquidity premium quantified

The price difference between on-the-run and off-the-run Treasuries is small but measurable. Off-the-run bonds typically yield 1 to 20 basis points more than on-the-run bonds of the same maturity. Longer-maturity bonds (10-year, 30-year) show larger premiums than shorter bonds (2-year, 5-year).

This premium is not due to credit risk or maturity—both bonds are backed by the same U.S. government. The only difference is age and trading convenience.

The premium persists as long as the off-the-run bond remains off-the-run. Once a new auctioned bond replaces the old off-the-run issue, the old bond may find new use in specialized corners of the market (e.g., repos, hedging, stripped bonds) and its premium can compress. But while a bond is “old and off-the-run,” traders avoid it.

Bid-ask spreads as the real cost

The financial impact of on-the-run status is not the yield difference alone, but the bid-ask spread.

A dealer might bid 99.50 for an on-the-run 10-year Treasury and ask 99.51 (a 1 basis point spread). The same dealer might bid 99.40 for the off-the-run version and ask 99.50 (a 10 basis point spread). The wider spread on the off-the-run bond reflects lower trading volume and dealer reluctance to hold inventory of the less liquid security.

For large institutional traders, this translates into real money. A pension fund or hedge fund buying $100 million of off-the-run bonds instead of on-the-run might lose $10,000–$100,000 in implicit trading costs (depending on the spread). Over time, these costs accumulate.

Market segmentation and dealer behavior

The on-the-run/off-the-run split is a form of market segmentation. Dealers segregate their inventory, maintain separate pricing models, and manage risk differently for each. Dealers are comfortable holding large positions in on-the-run bonds because they can offload them quickly. Off-the-run inventory is riskier; dealers charge higher spreads to compensate.

This behavior is rational but it reinforces the premium. Because off-the-run bonds are wider and riskier to hold, dealers avoid them unless compensated. Demand for off-the-run bonds drops, which widens spreads further, which reinforces the perception that they are illiquid.

This is a self-fulfilling dynamic: on-the-run bonds are popular because they are popular.

Uses of off-the-run Treasuries

Despite the premium, off-the-run Treasuries do get traded and held. They find demand in several niches:

• Repo markets: Dealers finance inventory using on-the-run bonds as collateral, so off-the-run bonds are sometimes cheaper to finance.
• Stripped bonds: Financial engineers disassemble off-the-run Treasuries into STRIPS (separate principal and coupon payments), which are useful for immunizing future liabilities.
• Relative value trades: Traders betting that the on-the-run/off-the-run premium will narrow (called “roll trades”) can profit by buying the cheap off-the-run bond and shorting the on-the-run bond.
• Yield enhancement: Some mutual funds and conservative portfolios intentionally buy off-the-run Treasuries to pick up the extra yield, accepting modest illiquidity to improve returns.

In the COVID-19 market stress of March 2020, off-the-run Treasuries became severely depressed (spreads widened dramatically) because dealers had to raise cash and liquidated positions indiscriminately. The Federal Reserve eventually intervened by purchasing substantial amounts of off-the-run bonds to normalize the market.

The role of new auctions

The Treasury’s auction schedule keeps on-the-run/off-the-run churn predictable. Every month, a new 10-year Treasury is auctioned. Dealers know the date and size in advance. Smart traders often position themselves before the auction—buying the current on-the-run and shorting the new issue in anticipation of the roll.

This roll opportunity is where many dealers extract profits. If you own the off-the-run 10-year on the day before a new 10-year auction, you might sell it to an investor and simultaneously buy the new issue as it comes live. The yield difference between the two is locked in as trading profit.

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