SOFR vs Fed Funds Rate

SOFR (Secured Overnight Financing Rate) is the volume-weighted median of overnight Treasury repo transactions. April 2026: SOFR approximately 3.62 percent, daily volume approximately $2 trillion. SOFR is published by the Federal Reserve Bank of New York at 8:00 AM ET each business day, reflecting the prior day transactions.

The effective fed funds rate (EFFR) is the volume-weighted median of overnight federal funds transactions among depository institutions. April 2026: EFFR approximately 3.63 percent, well within the FOMC target range of 3.50 to 3.75 percent. EFFR is published daily by the New York Fed. The pair compares secured (collateralized by Treasuries) overnight funding versus unsecured (interbank) overnight funding. Normal spread: SOFR within plus or minus 5 basis points of EFFR.

SOFR is secured: lenders receive Treasury collateral against the overnight loan. Default risk is essentially zero (the Treasury collateral is liquid and high-quality). EFFR is unsecured: depository institutions lend to each other based on credit standing. Default risk is small but non-zero.

In normal markets, secured and unsecured overnight rates converge because the additional credit risk on EFFR is small (banks rarely default on overnight loans). Theoretically, EFFR should slightly exceed SOFR by approximately 1 to 5 basis points (representing the credit risk premium on unsecured lending). In stress, the spread can widen substantially: secured rates remain anchored to Fed policy while unsecured rates spike on credit concerns. The 2008 GFC saw the related TED spread (3-month LIBOR minus 3-month T-bill) blow out to 460 basis points in October 2008.

Long-run SOFR-EFFR spread (since SOFR launched 2018): plus or minus 5 basis points, with EFFR slightly above SOFR on average. April 2026: SOFR 3.62 percent vs EFFR 3.63 percent (1 basis point spread, EFFR above).

The Fed targets EFFR within the FOMC range, and SOFR typically tracks within a few basis points. The Fed influences SOFR through Treasury repo operations: the Standing Repo Facility (SRF) sets a ceiling, and the Reverse Repo Facility (RRP) sets a floor (currently approximately $200 billion in usage versus $2.5 trillion peak in 2023). Both rates are mechanically tethered to Fed policy. The system functions as a corridor: SRF caps SOFR at 3.75 percent, RRP floors SOFR at 3.55 percent, and EFFR sits in the middle of the corridor.

September 17, 2019 produced the largest SOFR spike since SOFR launched. SOFR briefly traded as high as 5.25 percent versus EFFR at 2.13 percent (target range 2.00 to 2.25 percent), a 315 basis point spread. The spike was caused by Treasury repo collateral scarcity: Treasury auction settlements plus corporate tax payments drained liquidity from the repo market simultaneously, and dealer balance sheets were too constrained to provide short-term funding.

The Fed responded with overnight repo operations starting September 17, scaled to $75 to $120 billion per day. By September 18, SOFR retraced to 2.50 percent, and by month-end SOFR returned to normal range. The episode demonstrated that secured overnight funding is not perfectly anchored to Fed policy when collateral and dealer balance sheets are constrained, and led directly to the creation of the Standing Repo Facility in July 2021.

SOFR launched April 2018 as the U.S. LIBOR replacement after the LIBOR scandal (2012). Major U.S. dollar LIBOR tenors phased out by June 30, 2023. SOFR adoption: by June 2023, SOFR captured approximately 95 percent of new floating-rate loan issuance. SOFR derivatives trading volume now exceeds the peak of LIBOR derivatives volume.

Differences from LIBOR: SOFR is fully transactions-based (vs LIBOR survey-based, which enabled manipulation), reflects only secured overnight financing (vs LIBOR which embedded credit risk), and has approximately $2 trillion daily volume (vs LIBOR which had thinner observable transaction base). The transition has been smoother than initially feared, with most legacy contracts converting to SOFR plus credit adjustment spread (CAS) of 11 to 26 basis points to compensate for the credit risk component lost.

The Fed launched the Standing Repo Facility (SRF) in July 2021 as a permanent policy tool to backstop SOFR. The SRF allows primary dealers and depository institutions to borrow overnight against Treasury and agency MBS collateral at a rate set above the FOMC target.

April 2026 SRF rate: 3.75 percent (matching the upper end of the 3.50 to 3.75 percent FOMC range). The SRF effectively caps SOFR at 3.75 percent because any participant facing higher rates in the open repo market would simply borrow from the Fed at 3.75 percent. SRF usage has been minimal (essentially zero in normal periods), but the existence of the facility prevents the type of September 2019 spike from recurring. The SRF plus the RRP together create a corridor system that keeps SOFR anchored to Fed policy.

2024 to early 2026 has seen the most stable SOFR-EFFR spread since SOFR launched. The average daily spread has been within plus or minus 3 basis points throughout the period, with no spikes above 10 basis points.

The stability reflects: (1) Fed easing 100 basis points September to December 2024 transmitted cleanly to both rates, (2) SRF backstop preventing collateral scarcity spikes, (3) RRP usage drained from $2.5 trillion peak to $200 billion (releasing collateral back to the market), (4) record stable Fed policy framework with paused fed funds since December 2024. Iran war Q1 to Q2 2026 produced no measurable funding stress; SOFR-EFFR spread has held within 1 to 2 basis points throughout.

December typically produces seasonal funding stress as bank balance sheets contract for regulatory reporting. Historical year-end SOFR spikes: December 2018 (SOFR plus 35bp at year-end), December 2019 (spike contained by Fed pre-announced repo operations), December 2020 (no spike, ample reserves), December 2021 (no spike), December 2022 to 2025 (no spikes).

The Fed pre-announces year-end repo operations by mid-December, signaling commitment to backstop the funding market. December 2026 expectations: RRP usage approximately $200 billion entering year-end, SRF available, no expected spike. The post-2021 SRF era has effectively eliminated year-end funding stress as a market concern. The seasonal pressure has shifted from funding-rate volatility to a non-event, reflecting the structural improvements in Fed policy plumbing.

Setup 1 (60 percent probability): Continued quiet. SOFR-EFFR spread remains within plus or minus 5 basis points. Fed targets unchanged at 3.50 to 3.75 percent. No tradable signal from this pair. Trade: ignore the pair, focus on other indicators.

Setup 2 (20 percent): Year-end funding stress. December 2026 collateral scarcity drives SOFR briefly higher. Spread widens to 20 to 50 basis points for 1 to 3 days. Fed responds via repo operations. No lasting effect. Setup 3 (15 percent): Modest stress. Sustained spread of 10 to 20 basis points reflects mild collateral scarcity. SRF usage rises modestly. Indicates dealer balance sheet constraints emerging. Setup 4 (5 percent): Acute funding stress. Spread spikes above 50 basis points. Indicates serious repo market dysfunction. Fed intervenes aggressively via large-scale repo operations or balance sheet expansion.

Basic dashboard: track daily SOFR-EFFR spread alongside RRP usage and SRF usage. April 2026 levels: SOFR 3.62 percent, EFFR 3.63 percent, spread minus 1 basis point.

Three signals. First, spread above 10 basis points sustained for more than 5 days signals dealer balance sheet stress. Second, spread above 50 basis points in a single day signals acute collateral scarcity (rare since SRF launch in 2021). Third, RRP usage compression below $50 billion combined with rising SOFR-EFFR spread signals system reserves becoming scarce, a precursor to broader funding stress. SOFR-EFFR is normally a non-event; when it deviates it is highly informative. The September 2019 episode showed that even the largest spike resolved within 24 to 48 hours via Fed repo operations, so the trade window is short but the signal value is high.