Interbank rate

The interbank rate is the exchange rate at which large banks transact with each other in the wholesale currency market. Volumes are measured in millions of units of currency per trade; spreads at this level are extremely tight (often 0.01-0.05 percentage points).

For practical retail purposes, the interbank rate is synonymous with the mid-market rate — both refer to the midpoint between the wholesale bid and ask prices. The ECB’s daily reference rate is derived from interbank quotes; Reuters and Bloomberg publish near-real-time interbank snapshots; Convertitive’s currency converters use the ECB-derived rate.

You won’t get the interbank rate as a retail customer. Retail conversions add a spread of 0.3% (Wise) to 4%+ (traditional bank wires) on top. Card-network rates (Visa, Mastercard) typically sit between these — close to mid-market for the network itself, with the issuing bank then layering its own 1-3% foreign-transaction fee on top of the conversion. Reading a card statement, the difference between the “exchange rate” line and the actual interbank mid is the all-in cost of conversion; for travel-heavy spenders this is the single most impactful card-choice variable.

How interbank quotes are formed: there is no central exchange for FX — it’s an over-the-counter market dominated by ~15 large dealer banks (JPMorgan, Citi, Deutsche Bank, UBS, HSBC and others) trading via electronic platforms like EBS and Refinitiv Matching. The most-quoted pair, EUR/USD, sees roughly $2 trillion of notional turnover per day across spot, forwards, and swaps according to the BIS Triennial Survey. Liquidity is highest during the London-New York overlap (1300-1700 UTC); spreads widen sharply outside this window and across major holidays. Related: currency converter, mid-market rate. Reference rate sources: ECB euro reference rates.

The retail spread, with numbers

Suppose the EUR/USD interbank mid sits at 1.0850 on a given afternoon. The wholesale bid/ask spread is typically 1.0849/1.0851 — a 2-pip total cost. A retail customer wiring €10,000 to a US account through a traditional bank often sees a quoted rate around 1.0440 (a 3.8% markdown vs the interbank mid) plus a $25-45 wire fee. That same €10,000 transferred via Wise at a 0.35% margin lands at roughly 1.0812 plus a flat ~$8 fee — the all-in cost drops from about $410 to about $46 for the same transfer. A Visa or Mastercard cross-border purchase typically prices near 1.0830 (network spread ~0.2%) before the issuing bank’s foreign-transaction fee adds another 1-3%, so a no-foreign-fee card recovers most of the interbank advantage. These spreads are the reason “0% commission” bureau-de-change quotes can still be expensive — the markup is hidden in the rate, not the fee.

Why interbank rates move

Short-term interbank quotes are driven by order flow imbalances; medium-term moves reflect interest-rate differentials (covered interest parity); long-term moves track inflation differentials and balance-of-payments dynamics. Central-bank meetings (FOMC, ECB Governing Council, BoE MPC) are the most predictable volatility events — quotes can move 50-100 pips in seconds around a surprise decision. Reference: BIS Triennial Central Bank Survey of FX and OTC Derivatives Markets, 2022.