TBILLYIELD in Collabora Office: Calculate a Treasury-Bill Yield from Its Price

=TBILLYIELD(Settlement; Maturity; Price)

Settlement is the purchase date, Maturity is the expiry date, and Price is the purchase quote per 100 currency units of par. All three arguments are required.

There is no Basis, coupon-rate, or redemption-value argument. Do not append a fourth parameter copied from a different financial function. Enter the price as 98.45, not 98.45%.

The result is a decimal rate. Percentage formatting turns 0.091417 into about 9.1417%; it does not change the underlying number. Create dates with DATE rather than ambiguous date text.

Put =DATE(1999;3;31) in A2, =DATE(1999;6;1) in B2, and 98.45 in C2. In D2 enter =TBILLYIELD(A2;B2;C2).

The actual date interval is 62 days. The independent simple-yield arithmetic consistent with the documented control is:

=(100-C2)/C2*360/(B2-A2)

It gives approximately 0.091416962925, or 9.1416962925%, agreeing with the source’s rounded 9.1417%. The gain of 1.55 is divided by the invested price 98.45 before annualization.

For settlement 2026-01-01, maturity 2026-06-30, and price 98, the actual interval is 180 days. Use:

=TBILLYIELD(DATE(2026;1;1);DATE(2026;6;30);98)

The independent expected rate is (100−98)/98×360/180, approximately 4.081632653%. The holding-period gain is about 2.040816327%, annualized by two under this model.

A total face amount of 1000 instead of 100 would change cash amounts to 980 and 1000, but the percentage ratio remains the same. Keep the function’s per-100 quote convention intact.

For the 180-day example, the same 2-unit gain measured against par is 2/100=2% for the holding period. Annualized on 360 days, that discount rate is 4%.

TBILLYIELD’s investment-based rate is approximately 4.081632653%, because its denominator is 98. The difference is not an error or rounding issue; the rate definitions differ.

A 365-day simple annualization of the investment gain would be approximately 4.138321995%. This is another convention and should not be silently substituted for the model matching the documented TBILLYIELD example.

For an independent annual simple yield r and day count d in the displayed 360-day model, solve the arithmetic for price:

=100/(1+r*d/360)

Using r=0.0408163265306122 and d=180 reconstructs approximately 98. In a workbook, reference the unrounded result and day-count cells instead of typing rounded constants.

This audit reveals a misplaced percentage or an incorrect denominator. ROUND can format a quoted price, but premature rounding can prevent an inverse check from reproducing the exact original input.

Use valid dates with maturity after settlement and a positive quoted price. Zero price or zero elapsed time makes the displayed independent formula divide by zero; this mathematical observation is not a tested native error-code claim.

The dedicated section does not give a complete maximum-span rule, coercion matrix, or native error table. The worked controls use short intervals within one calendar year. Do not infer boundary behavior from another product’s similarly named function.

The result does not include taxes, fees, compounding, or a live market quotation. It is a mathematical rate from the supplied price and dates, and should be labeled with its convention rather than presented as a universal annual return.

The exact function is documented in Collabora Office 26.04 desktop help, retrieved and reviewed on October 17, 2026. This establishes a documentation scope, not the first release that introduced the function or the last version in which it works; those versions and any retirement date remain unestablished. Collabora Online and mobile support are not inferred from desktop help, nor is behavior in another spreadsheet product.

The examples are documentation-based expectations with independent calculations. They have not been executed in Collabora Office. No application screenshot or native error/coercion certification is implied. Formulas use English function names and semicolon argument separators.

• Collabora Office 26.04: TBILLYIELD (checked October 17, 2026).
• Editorial testing standards.