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Bid-to-Cover Ratio

The bid-to-cover ratio is the total dollar value of bids submitted in a Treasury auction divided by the amount actually sold. It is the fastest single read on demand: a ratio of 2.5 means investors bid for two and a half times the paper on offer.

Traders watch it because it summarizes appetite for duration at the current yield level. A ratio well above the recent average for that tenor signals strong sponsorship and often coincides with a stop-through; a weak ratio suggests dealers had to absorb unwanted supply and frequently accompanies a tail.

  • Rough desk baselines: 10-year notes tend to cover around 2.4–2.6x, 4-week bills often above 2.8x.
  • Levels only matter relative to that maturity’s own history: comparing a bill cover to a bond cover is meaningless.

Worked example: Treasury offers $42 billion of 10-year notes and receives $107.1 billion in bids. Bid-to-cover is 107.1 / 42 = 2.55x. If the trailing six-auction average is 2.48x, that is a modestly strong result, and if the auction also stops 1.2 basis points through the when-issued yield, the market reads it as clean, genuine demand rather than dealers reluctantly warehousing supply.

On the Helious desk right now

WORKED EXAMPLE: LAST FIVE 10-YEAR NOTE AUCTIONS, MEASURED BY HELIOUS
DATEHIGH YIELDBID-TO-COVERINDIRECT
4.683% 2.53 76.7%
4.580% 2.59 81.5%
4.538% 2.57 78.2%
4.468% 2.40 64.0%
4.282% 2.43 65.3%
Full history on the 10-Year Note hub.

FAQ

What is a good bid-to-cover ratio?

There is no single number: it depends on the tenor. A 2.5 is strong for a 30-year bond and unremarkable for a 4-week bill, so the only reading that means anything is against that tenor's own recent history. Helious publishes every auction's cover next to the tenor's trailing twelve-auction average on the auctions board, so the comparison is already made for you.

What does bid-to-cover actually measure?

Total bids divided by the amount the Treasury sold. A 2.5 means $2.50 was bid for every $1 issued. It measures the DEPTH of demand, not its quality, which is why it is read alongside the tail and the bidder split rather than on its own.

Is a falling bid-to-cover a warning sign?

Only when it persists and shows up with a tail. One soft cover is noise; several in a row on the same tenor, with the stop clearing above the when-issued yield, is the market asking for a concession to absorb supply. Helious tracks the twelve-auction average per tenor and ranks each result against the full captured history.
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