Every US Treasury coupon auction closes with five numbers that decide whether the strip reads the stop as strong, average, or fade. The high yield is the clearing rate the auction stopped at. The bid-to-cover ratio is total bids divided by the amount awarded. The tail is the gap between the high yield and the when-issued yield trading in the gray market at the 1:00 ET bidding deadline. The indirect bidder share proxies foreign and central bank demand. The primary dealer share is the residual, the piece the twenty-four dealers were left with when everyone else was done. The stronger the auction, the smaller the dealer residual.
The high yield
The Treasury runs a single-price Dutch auction. Bidders submit a yield they are willing to accept. Bids are filled from the lowest yield up, and every winning bidder pays the highest accepted yield, the stop. The high yield is the market-clearing rate for that day’s sale.
The stop matters less than the two comparisons around it. The first is the stop against the when-issued yield. The when-issued is the yield the same CUSIP trades at in gray-market forward trading during the days between announcement and settlement. It is the market’s live vote on where the auction should clear. The second is the stop against the on-the-run yield of the previous issue in the same maturity.
The bid-to-cover ratio
Total bids received divided by the amount awarded. If Treasury sells 69 billion of two-year notes and receives 175 billion of bids, the bid-to-cover is 2.54. The number reads relative to the trailing average for that maturity, typically the last twelve auctions.
Historical ranges by tenor sit roughly at 2.5 to 2.9 for the two-year, 2.4 to 2.7 for the five-year, 2.4 to 2.6 for the ten-year, and 2.3 to 2.6 for the twenty and thirty-year. A print above the trailing average reads as demand exceeding recent norms. A print below the average reads as fade. The bid-to-cover alone is a coarse read. It becomes signal when it moves in the same direction as the tail and the indirect share.
The tail
The tail is the stop minus the when-issued yield at the 1:00 ET auction deadline, measured in basis points. A stop-through or negative tail means the auction cleared below the when-issued yield: demand was stronger than the gray market expected, and the auction filled at a lower rate than the market had penciled in. A positive tail means the auction cleared above the when-issued: dealers had to price the residual higher to move it.
The threshold is small. A tail inside 0.5 basis points on a two-year, or inside 0.7 basis points on a thirty-year, is average. A stop-through of 1 basis point or more on a coupon auction is a clean strong read. A tail of 1.5 basis points or wider is fade.
The tail is the single most-watched number of the auction report because it is measured against real live market pricing at the deadline, not a rolling historical baseline. It answers the question the strip actually cares about: did the auction clear where the market thought it should.
The indirect bidder share
The Treasury breaks awards into three buckets. Indirects are bids routed through primary dealers on behalf of end clients, principally foreign central banks and reserve managers, sovereign wealth funds, and some domestic asset managers. Directs are bids from investors who bid on their own behalf without going through a dealer. Primary dealers are the twenty-four New York Fed counterparties who take down whatever is left.
The indirect share proxies foreign official demand, which is the deepest pool at the long end and the piece the Treasury needs to move duration without a term-premium repricing. Trailing averages sit roughly around 65 to 70 percent at the two-year, 70 to 75 percent at the ten-year, and 65 to 72 percent at the thirty-year, with wide variation.
A print above the trailing average is strong. A print at the average is neutral. A print 5 percentage points below the average is fade and typically pairs with a positive tail and an elevated dealer share.
The primary dealer share
The dealer share is the residual. It is the demand piece dealers were left holding when the auction closed. A low dealer share, running 10 to 14 percent at the ten-year or 12 to 16 percent at the thirty-year, means end-user demand cleared most of the issue. A high dealer share, running 20 percent or more, means dealers had to absorb a chunk they will have to distribute in the secondary market over the following days, and that distribution weighs on the on-the-run yield.
The dealer take is the cleanest single indicator of auction quality once you know how it typically runs for the specific tenor. Small residual is strong. Large residual is fade.
Reading the five numbers together
The five numbers are read as a cluster, not one at a time. A strong auction prints a small or negative tail, a bid-to-cover above the trailing average, an indirect share above average, and a dealer share below average. A weak auction prints a positive tail of 1 basis point or more, a bid-to-cover below average, an indirect share 5 points below average, and a dealer share of 20 percent or more. The cluster confirms whichever way it leans.
The stop reads matter for two channels. First, they tell the strip whether long-end duration is finding a natural home or is being warehoused by dealers, which sets short-term direction in the on-the-run yield. Second, over a rolling window of six to twelve auctions in the same tenor, they signal whether foreign official demand is stable, softening, or accelerating, which is the input to the term-premium repricing at the back end of the curve.
Sources and further reading
TreasuryDirect publishes auction announcements and same-day results at treasurydirect.gov. Full results include the CUSIP, the offering amount, the high yield, the bid-to-cover, and the awarded percentages by category (competitive tendered, competitive accepted, noncompetitive, indirect, direct, primary dealer). The New York Fed publishes the list of primary dealers and their operating framework at newyorkfed.org. SIFMA maintains reference material on the primary dealer system and auction mechanics.