SOFR vs EFFR
Last updated:
Direct answer
SOFR (Secured Overnight Financing Rate) and EFFR (Effective Federal Funds Rate) are both NY Fed-published overnight rates, but they measure different markets and serve different purposes. SOFR is the post-LIBOR USD derivatives benchmark, derived from ~$5T daily Treasury repo transactions. EFFR is the Fed's policy target rate, derived from ~$100B daily unsecured federal funds market. New USD derivatives reference SOFR; FOMC sets the target range on the federal funds rate. They typically run within 5-10 basis points of each other.
Why this question matters
If you're pricing a USD interest-rate swap, you reference SOFR. If you're modeling the Fed's reaction function or pricing the next FOMC meeting, you watch the federal funds rate. The two move together — SOFR is anchored to repo, which is anchored to Treasury bills, which are anchored to where banks can park overnight cash, which is anchored to the federal funds market — but they're not the same number and they're not interchangeable in a contract. LIBOR cessation in June 2023 made the SOFR vs EFFR distinction matter for thousands of derivatives contracts; teams that hadn't updated reference-rate logic by then ran into discrepancies measured in basis points × notional × time. Both rates publish ~8am ET for the prior business day; both are NY Fed products; both are free + public (no API key required). The distinction is structural, not paywall.
SOFR vs EFFR — side-by-side
| Dimension | SOFR | EFFR | Note |
|---|---|---|---|
| Publishing agency | Federal Reserve Bank of New York | Federal Reserve Bank of New York | Both NY Fed products since 2018 (SOFR launch) |
| Underlying market | Treasury repurchase agreements (repo) | Unsecured federal funds market — interbank lending | SOFR is secured (Treasury collateral); EFFR is unsecured |
| Daily transaction volume | ~$5 trillion | ~$100 billion | SOFR is 50x deeper — that's the case for SOFR as the new benchmark |
| Credit risk component | Risk-free (Treasury-collateralized) | Bank credit risk embedded (unsecured interbank) | Why SOFR replaced LIBOR — LIBOR had embedded bank credit; SOFR does not |
| Used as derivatives benchmark | Yes — all new USD derivatives reference SOFR post-2022 ARRC recommendation | No — EFFR was never the contract-reference rate; LIBOR was | ISDA fallback protocols moved $200T+ notional from LIBOR to SOFR |
| FOMC policy target | No — SOFR is observed, not targeted | Yes — FOMC sets the federal funds target range; EFFR is the observed realization | Common confusion — FOMC targets fed funds, NOT SOFR |
| Publication time | ~8am ET for prior business day | ~9am ET for prior business day | Both T+1 publication |
| History depth | Daily back to April 2018 (NY Fed launch); SOFR Indices back to 2018 | Daily back to July 1954 | EFFR has 70+ years of history; SOFR is the new kid |
| Term-structure variants | Term SOFR (1mo, 3mo, 6mo, 12mo) published by CME under license | No term variants — EFFR is overnight only | Term SOFR replaced term LIBOR (1mo / 3mo / 6mo / 12mo) for term-rate contracts |
| Spread to fed funds target | Typically 1-5bps above the lower bound of the fed funds target range | Typically near the middle of the FOMC target range | SOFR sometimes spikes (quarter-end, year-end) when repo demand outstrips supply |
| Best for | Pricing USD interest-rate swaps, floating-rate notes, ARM mortgages (post-2023) | Modeling Fed reaction function, pricing fed funds futures, policy-path analysis | They're complements, not substitutes |
Numbers worth remembering
- SOFR daily transaction volume is ~$5 trillion — roughly 50x the ~$100 billion daily volume of the unsecured federal funds market underlying EFFR.
- LIBOR cessation completed June 2023 for most tenors; ISDA fallback protocols moved over $200 trillion notional of derivatives from LIBOR to SOFR.
- SOFR publishes ~8am ET for the prior business day; EFFR publishes ~9am ET for the prior business day. Both are T+1.
- EFFR has daily history back to July 1954 (NY Fed publishes the full series); SOFR has daily history only back to April 2018 — that's a 64-year history-depth gap.
- SOFR-vs-EFFR spread is typically 0-10bps under normal conditions; SOFR has spiked to 30-60bps over EFFR during quarter-end repo stress events (most recently 2019 repo crisis).
- Term SOFR is published by CME under license (not the Fed); it covers 1-month, 3-month, 6-month, and 12-month tenors and replaced term LIBOR for term-rate derivatives contracts.
How to pull this data
When the Tidore macro vertical ships, both rates are available via one API key. Today the primary source is NY Fed directly (no API key required; CSV downloads + JSON endpoints).
# Tidore (in development, M3+ release) — pull both rates from one API key
curl -H "Authorization: Bearer $TIDORE_API_KEY" \
"https://api.tidore.co/v1/macro/sofr?from=2018-04-01"
curl -H "Authorization: Bearer $TIDORE_API_KEY" \
"https://api.tidore.co/v1/macro/effr?from=2018-04-01"
# Today — pull from NY Fed primary sources (free, no key)
# SOFR: https://www.newyorkfed.org/markets/reference-rates/sofr
# EFFR: https://www.newyorkfed.org/markets/reference-rates/effrAuthoritative sources
Frequently asked questions
Why did the Fed switch from LIBOR to SOFR (not EFFR)?
Three reasons. (1) Depth — SOFR's underlying Treasury repo market is ~$5T daily; EFFR's federal funds market is ~$100B; LIBOR was based on expert-judgment submissions that became thinly evidenced after 2008. (2) Manipulation resistance — SOFR is observed from actual transactions (overnight Treasury repo); LIBOR was submission-based and famously manipulated (2012 LIBOR scandal). (3) Risk-free anchoring — SOFR is Treasury-collateralized, so it has no bank credit risk embedded; LIBOR had embedded credit risk that distorted derivatives pricing during banking stress events.
Does the Fed target SOFR or fed funds?
The FOMC sets a target RANGE on the federal funds rate (not SOFR). The Fed manipulates the federal funds rate through open-market operations (reverse repo facility, IOER, etc.). SOFR is OBSERVED, not targeted — it moves in response to repo-market conditions, which the Fed influences indirectly through Treasury operations. Common confusion in headlines: "Fed raises rates" means "FOMC raises the fed funds target range," which moves EFFR up; SOFR follows but isn't the policy lever.
When should I use SOFR vs EFFR?
Pricing a USD interest-rate swap, floating-rate note, or post-2023 ARM mortgage — SOFR. Modeling Fed reaction function, pricing fed funds futures, analyzing FOMC policy path — federal funds (EFFR is the observed; the futures market trades the target). For backtesting pre-2023 derivatives data — LIBOR for the historical period, with cessation-aware switch to SOFR for the modern continuation.
How often do SOFR and EFFR diverge meaningfully?
Under normal conditions, they're within 0-10bps of each other and move together. The notable divergence events are quarter-end and year-end repo stress (when bank balance-sheet windows close and repo demand outstrips supply); SOFR has spiked 30-60bps over EFFR during these episodes (most famously the September 2019 repo crisis). The Fed's standing repo facility (2021+) has reduced but not eliminated these spikes.
What is Term SOFR and how is it different from overnight SOFR?
Overnight SOFR is the rate on overnight Treasury repo transactions. Term SOFR (1mo / 3mo / 6mo / 12mo) is published by CME under license and represents the expected forward-path of overnight SOFR over those tenors — effectively a forward-rate curve published as a single number per tenor. Term SOFR was created specifically to replace term LIBOR (which had 1/3/6/12-month tenors) for contracts that need a forward-looking term rate rather than a backward-looking compounded overnight rate.
Are SOFR and EFFR free to access?
Yes — both are NY Fed public-data products with no API key required and no licensing fee. CSV downloads and JSON endpoints are available directly from newyorkfed.org. Term SOFR is published by CME under a license that allows free academic + research use but has commercial-use fees for high-volume integrations. When Tidore's macro vertical ships, both rates will be available via one API key alongside other macro indicators for unified data quality envelope + multi-source disagreement guardrails.