LIBOR
LIBOR (London Interbank Offered Rate) was the world's most widely referenced interest rate benchmark, representing the average rate at which major global banks estimated they could borrow unsecured funds from each other in the London interbank market across multiple currencies and tenors. Following a manipulation scandal and declining transaction volume, LIBOR was formally discontinued for most currencies in June 2023 and replaced by risk-free rates such as SOFR (Secured Overnight Financing Rate) in the United States.
Key takeaways
- At its peak, LIBOR underpinned approximately $350 trillion in financial contracts globally, including adjustable-rate mortgages, corporate loans, floating-rate bonds, interest rate swaps, and student loans.
- LIBOR was administered by the British Bankers' Association (later ICE Benchmark Administration) and was set daily based on submissions from a panel of contributing banks—a survey-based methodology rather than actual transactions.
- The LIBOR manipulation scandal (uncovered 2012) revealed that panel banks had systematically misquoted their submission rates for years, both to profit from their derivatives positions and to appear healthier during the financial crisis.
- The transition from LIBOR to risk-free rates (RFRs) such as SOFR, SONIA (UK), €STR (Eurozone), TONA (Japan), and SARON (Switzerland) was completed for most currencies by mid-2023, replacing the interbank credit component with secured overnight transaction-based benchmarks.
- SOFR differs from LIBOR in being backward-looking (based on overnight Treasury repo transactions) rather than forward-looking and in not incorporating a bank credit risk premium, requiring adjustment of contract economics when transitioning legacy LIBOR contracts.
Explanation
LIBOR was first formalized in 1986 by the British Bankers' Association as a standardized measure of the short-term funding costs of major international banks. It was published daily across five currencies (USD, EUR, GBP, JPY, CHF) and seven maturities (overnight, 1 week, 1, 2, 3, 6, and 12 months), creating 35 rate series. The benchmark's dominance grew rapidly as it was embedded in virtually every type of floating-rate financial instrument: syndicated loans, floating-rate notes, interest rate swaps (where one leg pays LIBOR and the other pays a fixed rate), cross-currency swaps, caps and floors, and even retail financial products like adjustable-rate mortgages in the United States.
The methodology that created LIBOR's widespread adoption also contained its fatal flaw. Rather than being calculated from actual transactions, LIBOR was set through a 'waterfall' methodology where contributing banks submitted their estimate of the rate at which they 'could borrow' funds in reasonable market size. The absence of a transaction anchor created both ambiguity and the opportunity for manipulation. Beginning in the mid-2000s and continuing through the financial crisis, traders at major banks including Barclays, Deutsche Bank, UBS, Citigroup, and others colluded to submit rates that advantaged their derivatives positions—for example, pushing the 3-month USD LIBOR rate up or down to profit on their swap book or option positions. During the financial crisis, banks additionally submitted artificially low rates to avoid signaling financial weakness. The manipulation was exposed by investigative journalism and regulatory investigation beginning in 2012, resulting in $9+ billion in global fines and the conviction of several individual traders.
FCA Chief Andrew Bailey's 2017 announcement that the FCA would no longer compel panel banks to submit LIBOR quotes after 2021 triggered the global benchmark transition. The primary U.S. replacement, SOFR (Secured Overnight Financing Rate), is published by the New York Fed and is based on actual overnight repurchase agreement (repo) transactions secured by U.S. Treasury securities—roughly $1 trillion in daily transactions, making it almost impossible to manipulate. However, SOFR differs from LIBOR in two fundamental ways that complicated the transition: it is overnight (while LIBOR provided term rates for up to 12 months), and it contains no bank credit risk premium (as it reflects secured government funding costs, not unsecured interbank lending).
The LIBOR transition required amendments to hundreds of trillions of dollars of contracts. For derivatives, the ISDA IBOR Fallbacks Protocol established standardized fallback language replacing LIBOR with the compounded overnight RFR plus a credit spread adjustment (reflecting the historical average difference between LIBOR and the relevant RFR). For loans, the Secured Overnight Financing Rate was supplemented with Term SOFR rates (1M, 3M, 6M, 12M), published by CME Group based on SOFR derivatives transactions, which more closely mimic the forward-looking, term-rate structure that loan documents relied upon.
The economic implications of the LIBOR-SOFR spread are significant for fixed income analysis. A loan priced at 3-month LIBOR + 200 bps does not have identical economics to a loan at 3-month Term SOFR + 200 bps, because LIBOR incorporates an interbank credit premium (the LIBOR-OIS spread) that widens during periods of bank stress. Contracts transitioning from LIBOR to SOFR typically include a credit spread adjustment to compensate for this structural difference, but the adjustment is calculated as the historical median spread—which may not reflect future credit conditions.
Formula
LIBOR Rate = Trimmed Mean of Panel Bank Submissions (excluding highest and lowest quartiles)
Example
In July 2007, as the subprime mortgage market was beginning to unravel, 3-month USD LIBOR was approximately 5.32%, while the Federal Reserve's fed funds rate was 5.25% and the overnight index swap (OIS) rate was around 5.26%. The LIBOR-OIS spread of approximately 6 basis points was at historically normal levels. By September 2008, following the Lehman Brothers collapse, 3-month LIBOR had risen to 4.05% while the OIS rate fell to 1.66%, creating a LIBOR-OIS spread of 239 basis points—a signal of acute stress in the interbank lending market as banks refused to lend to each other unsecured. An interest rate swap portfolio with $1 billion notional that pays 3-month LIBOR and receives fixed 4.5% would have experienced a swing in the net present value of its LIBOR leg alone of approximately $6 million over this period, illustrating how the credit risk embedded in LIBOR creates unexpected P&L sensitivity for derivatives books.
Related terms
Basis Cheapest To Deliver Convexity Credit Risk Credit Spread Effective Duration Financial Crisis Interest Rate Interest Rate Swap Municipal Bond Net Present Value Option