Methodology

Fetched vs. computed

We fetch only two things. Everything else is computed here from those two inputs, so the method is fully transparent and reproducible.

How prices are computed

1. We interpolate the published par yield curve across maturities.
2. We bootstrap a spot (zero-coupon) curve from it on a semiannual grid — the rate to discount a single cash flow landing at any future date.
3. We lay out the bond's known cash flows (each coupon, plus principal at maturity) and discount each one at its spot rate. The sum is the dirty price.
4. Accrued interest (actual/actual) is subtracted to give the quoted clean price; yields and durations follow from the standard semiannual street-price convention.

These are indicative prices — matrix-priced model values off a public curve. They are not last-traded prices. Treasuries trade at small spreads to the curve (liquidity, on/off-the-run, financing), so a real execution will differ.

Data licensing & provenance

• Government sources (TreasuryDirect, the Treasury par curve) are U.S. public-domain data, freely redistributable. Treasury publishes its own CUSIPs, so there is no identifier-licensing issue for Treasuries.
• Every price is labelled by provenance: indicative / computed here. Future phases will label last-traded (TRACE/EMMA) and evaluated-feed prices distinctly.
• For data we do not have a clean right to re-host (e.g. municipal records), the plan is to deep-link to the authoritative source rather than copy it.

Corporate bonds — how they're priced here

Corporate bonds use the same engine as Treasuries, with a credit spread added. A bond's cash flows are discounted off the Treasury curve plus an indicative credit spread for its rating — these spreads are our own published model assumptions (not redistributed third-party index data), so the figure is transparent and fully ours. It is a model spread by rating, not an observed market spread — it will not capture issuer-specific or liquidity-driven moves, and should be read as our model's assumption:

Preview scope. Issuer identity (logo, ticker, sector) is live, but the individual bonds shown are a representative sample, not a full per-CUSIP universe, and the prices are indicative model values, not last trades. Complete coverage and real last-trade prices require a licensed market-data feed (FINRA TRACE), which is a separate paid add-on. Bond identity is shown as issuer-coupon-maturity shorthand rather than a CUSIP (CUSIP display is separately licensed).

Scope & roadmap

Treasuries (live): U.S. bills, notes and bonds priced off the curve. TIPS are priced on a real-yield basis off the Treasury Real Yield Curve (published 5y–30y; the real price/yield is shown, with the CPI index ratio not applied, so shorter TIPS aren't priced). FRNs are listed with terms only (their coupon resets off the 13-week bill rate).

Corporates (preview): grouped by issuer with live logos and tickers, indicatively priced off the Treasury curve + a model credit spread. A representative bond sample for now; full per-CUSIP coverage and real last-trade prices await a licensed data feed.

Next: municipals via deep links to the official record. The calculation layer is shared across all of them.

The visual language

A bond has no logo, and Treasuries have no brand at all — so identity comes from two colour systems, reused on every row and every phase.