Bills, notes, bonds, TIPS and FRNs: the differences

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

The US Treasury borrows through five kinds of marketable security. They differ in how long they last and in how they pay interest, and that changes how their auction results are quoted. At the end of August 2026 there were 463 of them outstanding: 49 bills, 241 notes, 112 bonds, 53 TIPS and 8 floating rate notes.

The five kinds at a glance

Why a bill has two rates

Bills pay no coupon. A bill is issued below face value and pays face value at maturity. Treasury quotes the result two ways:

• The discount rate is the discount as a share of face value, scaled to a 360-day year. It is the traditional quote and the one competitive bidders bid in.
• The investment rate is what the purchase price earns, scaled to a 365-day year. It is comparable with the yield on a note or bond, and it is always a little higher than the discount rate.

Example: the 13-week bill of 28 September 2026. The high discount rate was 4.110% and the investment rate 4.211%. For a 91-day bill with $100 of face value, a 4.110% discount means a price of about $98.961 (100 minus 100 × 0.0411 × 91 ÷ 360). Earning $1.039 on $98.961 over 91 days is 4.211% a year on a 365-day basis. (Our arithmetic from the published rates.) The bid-to-cover ratio was 2.99.

500metrics shows both rates on every bill page and names which one each sentence uses.

Reopenings, and why a 10-year note can be called "9-Year 11-Month"

A reopening adds to a security that already exists: same maturity date, same coupon, same CUSIP. Treasury does this to build up large issues that trade easily. The 10-year note and the 30-year bond are new issues four times a year, in the refunding months of February, May, August and November, and reopenings in the months between. The 2-, 3- and 7-year notes are always new issues.

Treasury labels a reopening by the time left, not by the original term. The 10-year note reopened on 9 September 2026 is listed as a "9-Year 11-Month" note, and the one due on 7 October 2026 as "9-Year 10-Month". People search for "10-year auction", so 500metrics files every reopening under the original term, says "reopening" next to it, and compares it with all 10-year note auctions.

Bills work the other way round. A 4-week bill can be a reopening of a bill first sold as a 17-week bill, because both mature on the same day. 500metrics files bills under the term offered at the auction.

Cash management bills

A cash management bill is a bill sold outside the regular weekly calendar, for an irregular term, to cover a short gap in Treasury's cash, for example in the weeks before large tax receipts arrive or while borrowing is close to the debt limit. Their results share one page for all cash management bills rather than a page per term.

What happens when a bill matures

On the maturity date Treasury pays the face value to whoever owns the bill. Treasury pays for maturing securities largely with the cash from new auctions settling the same day, which is why the maturity calendar and the auction calendar move together. The rate on a new bill is set by its own auction. 500metrics publishes each result once it is out and never forecasts the next one.

What this guide cannot tell you

• Which security suits anyone. 500metrics describes securities and their results; it does not compare them as investments.
• Tax treatment. Interest on Treasury securities has its own federal and state rules, which are outside this site.