SOFR LIBOR Transition: What Investors Need to Know

Key Takeaways

• USD LIBOR ceased on June 30, 2023; all new contracts must reference SOFR or another alternative rate, legacy LIBOR references in spreadsheets or documentation are broken.
• SOFR is a secured overnight rate computed as the volume-weighted median of Treasury repo transactions exceeding $1 trillion daily; LIBOR was an unsecured survey rate easily manipulated.
• Four SOFR variants exist: daily, 30/90/180-day compounded averages, the SOFR Index, and CME's forward-looking Term SOFR (1M, 3M, 6M, 12M).
• The ARRC credit spread adjustment for 3-month tenor is 26.161 bps, added to SOFR in legacy fallbacks to compensate for the structural gap between secured SOFR and unsecured LIBOR.

What It Is

SOFR is a broad measure of the cost of borrowing cash overnight when the borrower pledges US Treasury securities as collateral. It is published each business day at roughly 8:00 am ET by the Federal Reserve Bank of New York, in cooperation with the Office of Financial Research, based on actual transactions in the Treasury repo market.

LIBOR, the London Interbank Offered Rate, was a survey-based rate that estimated what large banks would pay to borrow from each other unsecured. LIBOR scandals between 2008 and 2012 revealed that traders had manipulated the submissions. Regulators globally began looking for a more transaction-based replacement, and US markets coalesced around SOFR.

The Intuition

LIBOR had two structural problems: the transactions underlying it were shrinking after the financial crisis as banks stopped lending unsecured to each other, and the submission process was vulnerable to manipulation. Any rate that sits under $200 trillion of contracts globally needs to be robust to both abuse and market stress.

SOFR solves both problems. Daily repo volumes run over $1 trillion, making manipulation effectively impossible and keeping the rate anchored in real trades even under stress. The trade-off is that SOFR is secured and overnight, while LIBOR was unsecured and term. That difference matters for users, as the two rates do not move identically.

How It Works

SOFR is calculated as the volume-weighted median of three segments of the Treasury repo market: tri-party repo, General Collateral Finance (GCF) repo, and cleared bilateral repo. The New York Fed trims outliers and publishes the rate along with the 1st, 25th, 75th, and 99th percentiles.

Because users often need a term rate rather than a single overnight print, four SOFR flavors exist:

• Daily SOFR, the raw overnight print
• SOFR Averages, compounded over 30, 90, and 180 calendar days (backwards-looking)
• SOFR Index, a cumulative compounded index useful for computing interest between any two dates
• Term SOFR, a forward-looking 1, 3, 6, and 12-month rate administered by CME Group and derived from SOFR futures

The simple compounded SOFR average over N days is:

Compounded SOFR = [Product over i=1..N of (1 + (SOFR_i * d_i / 360))] - 1

Where SOFR_i is the daily rate and d_i is the number of calendar days that rate applies (usually 1, or 3 over a weekend).

Key transition dates:

• April 2018: New York Fed begins publishing SOFR
• November 2020: Regulators tell banks to stop new LIBOR use by end of 2021
• December 2021: New USD LIBOR contracts discontinued
• April 2022: CME Term SOFR goes live
• June 30, 2023: All remaining USD LIBOR panel settings cease

Worked Example

Consider a floating-rate corporate loan that previously referenced 3-month USD LIBOR plus a 150 basis point credit spread. After transition, the loan references 3-month Term SOFR plus the same spread plus a credit spread adjustment (CSA) to compensate for SOFR being lower than LIBOR on average.

Suppose 3-month Term SOFR is 4.30 percent and the ARRC-recommended CSA for 3-month tenors is 26.161 basis points (0.26161 percent). The new coupon is:

Coupon = Term SOFR + CSA + credit spread
Coupon = 4.30 + 0.26 + 1.50
Coupon = 6.06%

That 26 basis point CSA is fixed and comes from the ISDA fallback protocol, calculated as the historical median spread between 3-month LIBOR and compounded SOFR over the five years before LIBOR's cessation announcement. Without the CSA, borrowers would have been given a rate cut at transition that lenders never agreed to.

Common Mistakes

1. Assuming SOFR is a drop-in replacement for LIBOR. SOFR is secured and includes no bank credit risk. During stress episodes, LIBOR historically widened while SOFR stayed pinned near the fed funds rate. Ignoring that structural difference can misprice long-dated contracts.

2. Confusing compounded SOFR with Term SOFR. Compounded SOFR is backwards-looking; Term SOFR is forward-looking. Loan documents must specify which variant and how many days. Mixing them creates basis risk.

3. Forgetting the credit spread adjustment. Legacy LIBOR contracts that fell back to SOFR without adjustment would have lost borrowers or lenders meaningful yield. The ISDA CSA exists precisely to preserve economic value at transition.

4. Using stale LIBOR references. Post-June 2023, USD LIBOR panel rates no longer exist. Any system, spreadsheet, or fallback language still pointing to "3M USD LIBOR" is broken and must be repapered.

5. Ignoring non-USD LIBORs. GBP, CHF, JPY, and EUR LIBOR followed their own transition paths to SONIA, SARON, TONA, and ESTR respectively. Multi-currency books need all five transitions, not just dollars.

Frequently Asked Questions

What is SOFR and why did it replace LIBOR? SOFR (Secured Overnight Financing Rate) is the overnight rate for borrowing cash against U.S. Treasury collateral, based on more than $1 trillion of actual daily transactions. LIBOR was a survey of what banks would hypothetically pay to borrow unsecured, a process revealed between 2008 and 2012 to have been manipulated. Regulators replaced LIBOR with transaction-based rates to eliminate that vulnerability.

When did LIBOR officially end? USD LIBOR panel settings ceased on June 30, 2023. New USD LIBOR contracts were banned at end-2021. Non-USD LIBORs (GBP, CHF, JPY, EUR) transitioned to SONIA, SARON, TONA, and ESTR on their own schedules. Any contract, spreadsheet, or system still referencing "3M USD LIBOR" after June 2023 is pointing to a rate that no longer exists.

What is the credit spread adjustment (CSA) and why does it matter? SOFR is secured (backed by Treasuries), while LIBOR was unsecured. A secured rate is structurally lower because the lender has collateral. The ARRC credit spread adjustment compensates for this structural difference: for 3-month tenor, the CSA is 26.161 basis points, calculated as the historical median spread between 3M LIBOR and compounded SOFR over five years before LIBOR's cessation. Without the CSA, legacy borrowers would have received a windfall rate cut at transition.

What is Term SOFR and how is it different from daily SOFR? Daily SOFR is a single overnight rate published each business day. Term SOFR is a forward-looking rate for 1-, 3-, 6-, and 12-month horizons, administered by CME Group and derived from SOFR futures. Term SOFR functions like LIBOR did, it tells you the rate for the whole period at the start, while compounded daily SOFR is only known at the end of the period. Most floating-rate loans prefer Term SOFR for operational simplicity.

How does SOFR behave differently from LIBOR in stress? LIBOR included an unsecured bank credit risk premium that widened during stress (Libor-OIS spread). SOFR is secured and stays anchored near the fed funds rate even in market stress, because Treasury collateral remains highly liquid. During the March 2020 dash-for-cash, SOFR barely moved while LIBOR-OIS widened sharply. This means SOFR does not automatically compensate floating-rate lenders for bank credit stress the way LIBOR did.

Sources

1. Federal Reserve Bank of New York, Alternative Reference Rates Committee. "Transition from LIBOR." https://www.newyorkfed.org/arrc/sofr-transition
2. Federal Reserve Bank of New York. "Secured Overnight Financing Rate Data." https://www.newyorkfed.org/markets/reference-rates/sofr
3. Alternative Reference Rates Committee. "How SOFR Works." https://www.newyorkfed.org/medialibrary/Microsites/arrc/files/2020/ARRC_Factsheet_2.pdf
4. CME Group. "Term SOFR." https://www.cmegroup.com/market-data/cme-group-benchmark-administration/term-sofr.html

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.