Reference data
The tables that feed every RungRate calculator, published in the open with their sources and as-of dates. If a number in a tool looks off, this is where to check it.
Current Treasury bill yields (4–52 weeks)
The latest published yields for every T-bill tenor, on both the bank-discount and investment-rate (coupon equivalent) basis, with the exact Treasury as-of date.
T-bill after-tax advantage by state
All 50 states plus DC, ranked by how much extra after-tax yield the state-tax exemption on Treasury interest is worth — and the CD rate needed to match a 4.00% T-bill.
State income tax top rates
Alphabetical 2026 reference: top marginal rate, flat vs graduated structure, whether interest is taxed, and local add-on caveats for every state.
National average CD & savings rates
The FDIC's monthly national deposit-rate benchmarks: savings, money market, and CDs from 1 to 60 months, with rate caps.
How these tables are maintained
Every table states its own source and as-of date next to the figures. Treasury yields are refreshed weekly, FDIC deposit benchmarks monthly, and tax rates annually — the full schedule and formulas are documented on the methodology page. The underlying constants are also published as machine-readable JSON (linked from each table page), which is the same data the calculators load.
Nothing here is copied from another comparison site. Figures are drawn from the U.S. Treasury, the FDIC, and state statutes as compiled by nonpartisan tax references, then cross-checked before publication. Corrections are welcome via the contact page.