LIBOR was replaced by the Secured Overnight Financing Rate, or SOFR, for U.S. dollar contracts, and by a set of similar overnight benchmarks in other major currencies. If you’re wondering what replaced LIBOR on your mortgage, student loan, or credit line, the answer is almost certainly a version of SOFR, and the swap happened automatically under federal law without anything required from you.1Federal Reserve Bank of New York. Secured Overnight Financing Rate Data
What SOFR Is
SOFR measures the cost of borrowing cash overnight against U.S. Treasury securities as collateral. Every business day, hundreds of billions of dollars change hands in the Treasury repurchase market, where one party sells Treasuries and agrees to buy them back the next day at a slightly higher price. That price difference is an overnight interest rate, and SOFR is the volume-weighted median of those trades.2Federal Reserve Bank of New York. Transition From LIBOR
Two features make SOFR structurally different from LIBOR. Every data point comes from a completed transaction rather than a bank’s estimate of what it might pay to borrow. And the underlying market is huge: daily repo volumes regularly exceed $3 trillion, which makes the rate almost impossible for any single institution to move.1Federal Reserve Bank of New York. Secured Overnight Financing Rate Data Because the collateral is U.S. government debt, SOFR is a near-risk-free rate. It does not include the bank credit risk premium that LIBOR carried, which matters when you get to spread adjustments below.
LIBOR, by contrast, was built on daily submissions from a panel of banks reporting what they thought they’d pay to borrow. Nobody was checking those numbers against real trades, and an international investigation beginning in 2012 found that traders at multiple banks had been coordinating their submissions to benefit their own positions. Regulators concluded that any benchmark built on estimates rather than verifiable transactions was a structural problem, and the transition to SOFR followed.
Term SOFR vs. Daily Simple SOFR
SOFR shows up in loan documents in two main forms, and they behave differently.
Daily Simple SOFR adds up the actual overnight rate published each business day during a billing period. The final interest charge is only known once the period ends, because each day’s rate feeds in one at a time. It reflects real market conditions with no forecasting, but you can’t calculate your exact payment until the period closes.
Term SOFR fixes that. Published daily by CME Group in one-month, three-month, six-month, and twelve-month tenors, it gives borrowers and lenders a single forward-looking rate at the start of the interest period. That structure closely mirrors how LIBOR worked, which is why Term SOFR has become the dominant choice for business loans and credit facilities, with more than 2,870 firms globally using it.3CME Group. CME Term SOFR Rates
For most consumer and commercial borrowers, Term SOFR is what appears in loan documents. If your adjustable-rate mortgage or business line of credit references SOFR, odds are it uses the Term version.
What Replaced LIBOR in Other Currencies
LIBOR existed in multiple currency versions, and each major economy adopted its own overnight replacement. All share SOFR’s design: overnight rates from actual transactions, not bank estimates.
- United Kingdom: SONIA, the Sterling Overnight Index Average, administered by the Bank of England.4Bank of England. SONIA Interest Rate Benchmark
- Eurozone: €STR, the Euro Short-Term Rate, administered by the European Central Bank.5European Central Bank. Overview of the Euro Short-Term Rate
- Japan: TONA, the Tokyo Overnight Average Rate, administered by the Bank of Japan.
- Switzerland: SARON, the Swiss Average Rate Overnight, based on repo transactions and administered by SIX, a private financial infrastructure company.6SIX Group. SARON Rate: Benchmark for Swiss Mortgages
Because these are all overnight rates anchored in real transactions, they strip out the bank credit risk premium that LIBOR included. Cross-border lenders add a spread on top of the relevant benchmark to account for credit risk and other costs, much as they did before.
What the Change Means for Your Loan
If you have a variable-rate product that once referenced LIBOR, it now references a SOFR-based rate. You didn’t need to refinance, sign anything, or take action; the transition happened on the back end.
Adjustable-rate mortgages are the most visible example. After the initial fixed-rate period ends, the loan’s rate resets periodically based on a benchmark plus a margin. Mortgages that once referenced LIBOR now reference a version of SOFR.
Private student loans with variable rates went through a similar automatic process. Servicers handled the mechanics, and industry guidance directed them to notify borrowers about how the change affected their specific loans.7Federal Reserve Bank of New York. LIBOR-Based Private Student Loan Transition Resource Guide
Credit cards and personal lines of credit with variable rates also transitioned. Because SOFR is a near-risk-free rate and doesn’t carry the bank credit component LIBOR did, lenders typically adjusted the margin so the total interest rate stayed roughly the same.
Commercial loans and corporate credit facilities make up the largest dollar volume of affected contracts. In that market, borrowers and lenders had more room to negotiate the specific SOFR variant and spread adjustment in their contracts.
The LIBOR Act Did the Work Automatically
Many older loan agreements and derivatives had no workable fallback language. Some had fallback provisions that pointed back to LIBOR itself, or required someone to poll banks about interbank lending rates, which was no longer possible. Without intervention, those contracts would have been legally ambiguous the moment LIBOR stopped publishing.
Congress addressed this by enacting the Adjustable Interest Rate (LIBOR) Act, codified at 12 U.S.C. Chapter 55. The law applies to contracts that either contain no fallback provisions, or contain fallback provisions that fail to identify a specific replacement benchmark or a person authorized to select one. For those contracts, the statute automatically substitutes a SOFR-based benchmark selected by the Federal Reserve Board.8Office of the Law Revision Counsel. 12 USC 5803 – LIBOR Contracts9Federal Reserve Board. Federal Reserve Board Adopts Final Rule That Implements Adjustable Interest Rate (LIBOR) Act
Fallback provisions that would have led to a dead end, such as those pointing to another LIBOR-dependent rate or requiring a bank poll, are automatically voided, and the Board-selected replacement takes over.8Office of the Law Revision Counsel. 12 USC 5803 – LIBOR Contracts
The Act also includes a safe harbor that protects lenders, servicers, and other parties from breach-of-contract claims for using the Board-selected replacement. This mattered because changing a benchmark would normally require mutual consent, which was impractical across millions of legacy contracts. The safe harbor does not excuse servicing errors: if a servicer miscalculates a payment or applies the wrong rate, your right to demand correction remains intact.10Office of the Law Revision Counsel. 12 USC 5804 – Continuity of Contract and Safe Harbor
Why Your Rate Didn’t Drop
Because SOFR is a near-risk-free rate and LIBOR wasn’t, a straight swap would have lowered the interest rate on every affected contract. That would have handed borrowers a windfall at lenders’ expense and would not have reflected what the parties originally agreed to. The Act solves this with a fixed spread adjustment added on top of the SOFR-based replacement:11eCFR. Part 253 – Regulations Implementing the Adjustable Interest Rate (LIBOR) Act (Regulation ZZ)
- Overnight: 0.00644 percent
- One-month: 0.11448 percent (about 11.4 basis points)
- Three-month: 0.26161 percent (about 26.2 basis points)
- Six-month: 0.42826 percent (about 42.8 basis points)
- Twelve-month: 0.71513 percent (about 71.5 basis points)
Consumer loans got a gentler treatment during the first year after the replacement date. Rather than jumping immediately to the fixed spread adjustment, the regulation phased it in through a linear transition. The spread started at the actual difference between LIBOR and the new SOFR-based rate on the day before the switch, then moved gradually toward the statutory value over twelve months.12Federal Register. Regulations Implementing the Adjustable Interest Rate (LIBOR) Act The idea was to keep your payment from moving noticeably on a single date.
Notices You Should Have Received
Federal law required lenders to tell you before changing the benchmark on your loan, with timelines that depend on the product.
Adjustable-rate mortgages carry the longest lead time. For the first rate adjustment after the initial fixed period, your lender must send disclosures at least 210 days (and no more than 240 days) before the first adjusted payment is due. For later adjustments, the window is 60 to 120 days before the new payment amount takes effect. Switching from LIBOR to a comparable replacement like the Board-selected SOFR benchmark does not by itself count as adding a new variable-rate feature, so it doesn’t trigger a fresh round of initial disclosures.13Consumer Financial Protection Bureau. Disclosure Requirements Regarding Post-Consummation Events
Home equity lines of credit require at least 15 days’ advance notice before a change in the index or margin takes effect. Credit card accounts require at least 45 days. Both notices must disclose the replacement index and any adjusted margin, even if the margin decreased.14Federal Register. Facilitating the LIBOR Transition (Regulation Z)
Where the exact replacement rate was not yet published when notice needed to go out, lenders could send an estimate based on the best available information, provided they clearly labeled it as an estimate and indicated the rate would be substantially similar to what the borrower was already paying.14Federal Register. Facilitating the LIBOR Transition (Regulation Z) If you think a notice you received was inaccurate, or your payment doesn’t match the rate you were told about, the servicing-error protections outside the LIBOR Act’s safe harbor still apply.