What is a Treasury reopening?

Drafted with AI assistance from official sources; checked against the sources listed below.

A reopening is an auction of more of a Treasury security that already exists. The new amount has the same maturity date, the same coupon and the same CUSIP as the original issue, so once it is issued the two cannot be told apart.

Why Treasury reopens securities

Larger issues trade more easily. Instead of selling a new ten-year note every month, Treasury sells a new one in each quarterly refunding month and reopens it in the two months after. The thirty-year bond, the twenty-year bond and most TIPS run on similar cycles, and bills are often reopened as well.

How a reopening appears in the results

Treasury labels a reopening by the time left to maturity, so the ten-year note reopened a month after its first sale is listed as a "9-Year 11-Month" note. 500metrics files it under the original term and marks it as a reopening, so every ten-year note auction sits on one page.

How a reopening auction differs

• The coupon is already fixed. Bidders bid a yield as usual, and the price works out above or below par to match the high yield.
• Interest may already be owed. A buyer pays the interest that has built up since the last coupon date, and gets it back with the next coupon.
• Compare like with like. A reopening is still compared with every auction of its original term, and each row on 500metrics says "new issue" or "reopening".

What it does not tell you

• How much of the security is outstanding after the reopening. The monthly statement of the public debt has the total; the guide to what the US national debt is made of explains it.