Methodology for Determining Effective Rates


In determining the interest that account holders are paid on cash credit balances and charged on debit balances, each currency is assigned an IBKR Reference Benchmark rate. The IBKR Reference Benchmark rate is determined from short-term market rates but capped above/below widely used external reference rates or, where appropriate, bank deposit rates. This page explains how IBKR Reference Benchmark rates are determined.

Reference Rates

Reference rates are determined using a three-step process. The rates are capped above/below traditional external reference rates. For currencies and IBKR affiliates where Forex swap market pricing does not affect the rates we pay and charge our customers, Step 1 is omitted from the final rate determination.

1. Market implied rates

For market pricing, we utilize short-term Forex swap markets. Since most of the transactions involve the US dollar, Forex swap prices of currencies vs. the US dollar are sampled over a pre-determined time period referred to as the "Fixing Time Window" that is intended to be representative of liquid trading hours and primary turnover. The specific swap tenor and fixing windows used depend on the currency. We use the best bid and ask from a group of up to 12 of the largest Forex dealing banks to calculate the implied non-USD short-term rates - generally Overnight (T/T+1), Tom Next (T+1/T+2) or Spot Next (T+2/T+3). At the Fixing Time Window close, these calculations are sorted with the lowest and highest rates disregarded and the remainder averaged to determine the market implied reference rate.

2. Traditional external benchmark reference rates

For traditional benchmarks, we utilize published reference rates and, where appropriate, bank deposit rates. These rates generally are determined by either bank survey or actual transactions. The London Inter-Bank Offered Rate (LIBOR), for example, is determined by surveying a panel of banks for the rate at which they could borrow funds from other banks at a specific time each day. In contrast, the US dollar Fed Funds effective rate is calculated as the weighted average of interbank lending rates transacted in the Fed Funds market.

3. IBKR Reference Benchmark Rates

The final IBKR Reference Benchmark rates are then determined by using the market implied reference rate, as described in 1. above, but capped by a certain amount above/below the traditional external benchmark reference rate as described in 2. above. For currencies and IBKR affiliates where Forex swap market pricing is not relevant, the final IBKR Reference Benchmark rates are determined by using traditional benchmarks or bank deposit rates, capped as above. The caps can change at any time without explicit prior notice and are listed in the table below, along with relevant currency and benchmark reference rates.


a. Assume the market implied overnight rate for GBP is 0.55%. The overnight GBP LIBOR reference rate is 0.65%. The effective rate is then equal to the market implied rate of 0.55%, as it is still within the 1.00% cap around the LIBOR reference rate at 0.65%.

b. If, for example, the market implied rate for CNH was 4.5% but the overnight CNH reference rate for the same period was 1.0%, the effective rate would be capped at 2.0% above the CNH reference rate, or 3.0% (1.0% reference rate + 2.0% cap).

Note:  Caps can change any time without explicit prior notice.

Currency Benchmark Description Cap Below2 Cap Above2
USD Fed Funds Effective (Overnight Rate)  0.00% 0.00%
USD 11 am GMT USD LIBOR (used only for USD-CFDs, Gold and Silver Borrow Fees)  0.00% 0.00%
AUD RBA Daily Cash Rate Target  1.00% 1.00%
CAD Bank of Canada Overnight Lending Rate  1.00% 1.00%
CHF Swiss Franc LIBOR (Spot-Next rate) 1.00% 1.00%
CNY/CNH CNH HIBOR Overnight Fixing Rate (TMA) 2.00% 2.00%
CZK Prague ON Interbank Offered Rate 1.00% 1.00%
DKK Danish Tom/Next Index 1.00% 1.00%
EUR EONIA (Euro Overnight Index Average) 1.00% 1.00%
GBP GBP LIBOR (Overnight Rate) 1.00% 1.00%
HKD HKD HIBOR (Overnight rate) 1.00% 1.00%
HUF Budapest Interbank Offered Rate 1.00% 1.00%
ILS Tel Aviv Interbank Offered O/N Rate 1.00% 1.00%
INR Central Bank of India Base Rate 0.00% 0.00%
JPY JPY LIBOR (Spot-Next rate) 1.00% 1.00%
KRW Korean Won KORIBOR (1 week) 0.00% 0.00%
MXN Mexican Interbank TIIE (28 day rate) 3.00% 3.00%
NOK Norwegian Overnight Weighted Average 1.00% 1.00%
NZD New Zealand Dollar Official Cash Daily Rate 1.00% 1.00%
PLN WIBOR (Warsaw Interbank Overnight Rate) 1.00% 1.00%
RUB RUONIA (Ruble Overnight Index Average) 3.00% 3.00%
SEK SEK STIBOR (Overnight Rate) 1.00% 1.00%
SGD Singapore Dollar SOR (Swap Overnight) Rate 1.00% 1.00%
TRY TRLIBOR (Turkish Lira Overnight Interbank offered rate) 3.00% 3.00%
ZAR South Africa Benchmark Overnight Rate on Deposits (Sabor) 3.00% 3.00%


2 Caps or the deviation for the effective rate allowed above or below the benchmark fixing can change at any time without explicit prior notice.