How Is Libor Calculated

Calculate how LIBOR rates are determined based on interbank lending data and market conditions. This interactive tool demonstrates the calculation methodology used by contributing banks.

Comprehensive Guide: How Is LIBOR Calculated?

The London Interbank Offered Rate (LIBOR) was historically the most widely used benchmark for short-term interest rates globally. Though it has been largely phased out in favor of alternative reference rates like SOFR, understanding how LIBOR was calculated provides valuable insight into financial benchmarks and their impact on global markets.

1. The LIBOR Calculation Process

LIBOR was calculated through a waterfall methodology that incorporated both transaction-based data and expert judgment from panel banks. Here’s the step-by-step process:

1. Panel Bank Selection: A group of 11-16 major international banks were selected to contribute rates for each currency and tenor combination.
2. Daily Submissions: Each panel bank submitted the rate at which it could borrow funds in the interbank market at 11:00 AM London time.
3. Data Collection: The ICE Benchmark Administration (IBA) collected these submissions for each currency and tenor.
4. Outlier Removal: The highest and lowest 25% of submissions were discarded to create a “trimmed mean.”
5. Final Calculation: The remaining submissions were averaged to produce the published LIBOR rate.

2. Key Components of LIBOR Calculation

Component	Description	Impact on Calculation
Panel Banks	Major international banks selected for their active participation in interbank lending markets	Determines the quality and representativeness of submitted rates
Currency	USD, EUR, GBP, JPY, CHF were the main currencies with LIBOR rates	Affects the specific interbank market being measured
Tenor	Time periods ranging from overnight to 12 months	Different tenors reflect different risk profiles and liquidity conditions
Submission Time	Fixed at 11:00 AM London time each business day	Ensures consistency and allows for same-day publication
Trimmed Mean	Statistical method removing highest and lowest 25% of submissions	Reduces potential manipulation and reflects the market consensus

3. Mathematical Formula for LIBOR Calculation

The final LIBOR rate was calculated using this formula after outlier removal:

LIBOR = (Σ remaining_submissions) / (number_of_remaining_submissions)

Where:

• remaining_submissions = All submissions after removing the highest and lowest 25%
• number_of_remaining_submissions = Total submissions minus 25% from each end

4. Historical LIBOR Rates by Tenor (2020-2021)

Date	1 Month USD LIBOR	3 Month USD LIBOR	6 Month USD LIBOR	12 Month USD LIBOR
Jan 2020	1.68%	1.70%	1.73%	1.80%
Apr 2020	0.40%	0.45%	0.50%	0.65%
Jul 2020	0.18%	0.25%	0.30%	0.45%
Oct 2020	0.15%	0.20%	0.25%	0.35%
Jan 2021	0.12%	0.18%	0.22%	0.30%
Jun 2021	0.09%	0.13%	0.17%	0.25%

5. Factors Influencing LIBOR Rates

Several macroeconomic and market factors influenced LIBOR submissions:

• Central Bank Policy Rates: The Federal Reserve’s federal funds rate (for USD LIBOR) had the most direct impact, as panel banks based submissions partly on expectations of central bank actions.
• Credit Risk Premiums: During financial crises, banks added larger risk premiums to their submissions to account for increased counterparty risk.
• Liquidity Conditions: Tighter liquidity in interbank markets typically led to higher LIBOR submissions as banks competed for limited funds.
• Economic Indicators: Employment data, GDP growth, and inflation figures influenced expectations about future interest rates.
• Geopolitical Events: Major political events or crises could cause sudden spikes in LIBOR as banks perceived increased risk.

6. The Transition from LIBOR to Alternative Rates

Following manipulation scandals and structural changes in financial markets, regulators pushed for the transition away from LIBOR. The key alternatives include:

• SOFR (Secured Overnight Financing Rate): The primary replacement for USD LIBOR, based on actual transactions in the U.S. Treasury repurchase market.
• SONIA (Sterling Overnight Index Average): Replaced GBP LIBOR, based on actual overnight funding transactions.
• €STR (Euro Short-Term Rate): Replaced EUR LIBOR, reflecting the wholesale euro unsecured overnight borrowing costs.
• TONAR (Tokyo Overnight Average Rate): Replaced JPY LIBOR, based on uncollateralized overnight call transactions.
• SARON (Swiss Average Rate Overnight): Replaced CHF LIBOR, based on Swiss franc repo market transactions.

7. Common Misconceptions About LIBOR

Despite its widespread use, several misconceptions persisted about LIBOR:

1. “LIBOR was based purely on actual transactions”: In reality, especially for longer tenors, LIBOR often relied on expert judgment rather than observable transactions.
2. “All panel banks had equal influence”: While the trimmed mean method reduced individual bank influence, larger banks with more interbank activity had more reliable submissions.
3. “LIBOR represented a risk-free rate”: Unlike government bond yields, LIBOR included credit risk premiums reflecting interbank lending risks.
4. “LIBOR manipulation only affected a few rates”: The scandals revealed attempts to manipulate rates across multiple currencies and tenors.
5. “The transition from LIBOR was immediate”: The phase-out occurred over several years with extensive fallback provisions in contracts.

Authoritative Resources on LIBOR Calculation

For official information about LIBOR and its calculation methodology, consult these authoritative sources:

• Federal Reserve – LIBOR Transition Information
• Alternative Reference Rates Committee (ARRC) – SOFR Implementation
• Bank of England – SONIA Benchmark Information

Frequently Asked Questions About LIBOR Calculation

Q: Why was LIBOR discontinued?

A: LIBOR was discontinued primarily due to:

• Manipulation scandals where banks submitted false rates to benefit trading positions
• Declining liquidity in unsecured interbank lending markets (especially for longer tenors)
• Regulatory pressure for more transaction-based benchmarks
• The need for more robust, less manipulable reference rates

Q: How did banks determine their LIBOR submissions?

A: Panel banks used a hierarchical approach:

1. First priority: Actual transaction data from the interbank market
2. Second priority: Transaction-derived data (like brokered transactions)
3. Third priority: Expert judgment based on market conditions and funding costs

Q: What was the “LIBOR scandal” about?

A: The LIBOR scandal revealed that:

• Traders at multiple banks colluded to manipulate submissions
• Banks artificially lowered submissions during the 2008 financial crisis to appear healthier
• Manipulation occurred from at least 2005 through 2009
• Fines totaled over $9 billion across multiple financial institutions
• Several traders received prison sentences for their roles

Q: How does SOFR differ from LIBOR in calculation?

A: Key differences include:

Feature	LIBOR	SOFR
Underlying Market	Unsecured interbank lending	Secured Treasury repo market
Calculation Method	Survey-based (expert judgment)	Transaction-based (actual trades)
Credit Risk Component	Included bank credit risk	Nearly risk-free (secured by Treasuries)
Tenors Available	Multiple (overnight to 12 months)	Overnight only (term SOFR now available)
Publication Time	11:00 AM London time	8:00 AM New York time
Volume of Underlying Transactions	Declining (especially for longer tenors)	Over $1 trillion daily

Q: Can I still use LIBOR in new contracts?

A: No, regulatory guidance prohibits new use of LIBOR in most contracts:

• USD LIBOR: Most tenors ceased publication after June 30, 2023
• GBP, EUR, CHF, JPY LIBOR: All tenors ceased after December 31, 2021
• Some legacy contracts may continue using “synthetic” LIBOR for a limited period
• All new contracts should reference alternative rates like SOFR