The currency clause is a pricing clause.

Currency is a commercial term.

Most TSAs treat currency as an operational footnote. The price is in one currency, the invoice is in another, and the rate is whatever the seller's accounting policy says. That posture costs the buyer money. Currency is a commercial term, not an accounting convention. The currency clause defines the invoicing currency, the rate setting method, the timing of the rate, and the responsibility for currency fluctuation between the rate setting date and the payment date.

The default seller posture is to bill in the seller's home currency, set the rate at the seller's convenience, and let the buyer absorb the FX variance. That posture transfers the entire currency risk to the buyer. The disciplined buyer reverses the default. The buyer should bill in the buyer's planned operating currency, set the rate at a defined source on a defined date, and split the variance through a clear mechanism.

The size of this issue depends on the deal. For a domestic carve-out where both parties operate in the same currency, the currency clause is short. For a cross-border carve-out where the seller is a multinational and the buyer is a regional fund, the currency clause can move millions across the TSA period. The cross-border patterns that surface this issue are covered in cross-border TSA considerations.

Three rate models and what they do.

Model one is the fixed rate. A single FX rate is set at signing and applies for the entire TSA period. The fixed rate gives the buyer predictability. It also creates a windfall or a loss depending on where the spot rate moves over the period. Fixed rates favor the buyer when the seller's currency strengthens and the seller when the buyer's currency strengthens. Fixed rates work best for short TSAs where the FX exposure is small.

Model two is the periodic reset. The rate is reset monthly or quarterly to a published reference rate. The reset tracks underlying cost movements and removes the windfall risk on both sides. The reset adds administrative complexity and creates short term billing variance. Periodic reset is the standard model for TSAs of 6 months or more. The reference rate should be a published central bank rate or a major commercial bank fix, not the seller's internal rate.

Model three is the collar. The rate floats within a defined band. Above the upper bound or below the lower bound, the rate is capped at the bound. The collar limits the downside for both parties while preserving most of the rate sensitivity. Collars are useful when the underlying volatility is high and the parties want to put a ceiling on the exposure. Collars require a more careful drafting because the band defines who is exposed at the edges.

Pass-through mechanics across currencies.

Pass-through charges are the items where the seller reimburses third-party costs at cost plus a defined mark up. Most TSAs include software licenses, infrastructure, and external services as pass-through. When the underlying vendor invoices the seller in a third currency, the pass-through clause has to define how that third currency converts into the TSA billing currency.

The disciplined buyer requires the underlying invoice in the source currency, the rate used by the seller to convert, and the source of that rate. Without that triangulation, the seller can charge the buyer using a rate that produces a hidden margin on top of the agreed mark up. The triangulation is straightforward to verify when the seller provides the underlying invoice. The pattern of pass-through audit discipline is covered in TSA vendor cost pass-through audit.

Cross-border pass-through often triggers withholding tax. The TSA should specify which party bears the withholding, who is responsible for collecting tax documentation from the underlying vendor, and how the gross up calculation works. Without these clauses, a withholding obligation can appear on the buyer's books months after the original payment, with no contractual recourse.

The rate source is non-trivial.

The rate source matters more than most TSAs admit. A reference rate published by the European Central Bank or the Federal Reserve is reliable, transparent, and verifiable. A reference rate published by a single commercial bank is reasonable but introduces a single point of dependency. A reference rate sourced from the seller's internal accounting system is unverifiable and should be rejected.

The rate timing matters too. A spot rate set on the invoice date includes the volatility of any single trading day. A monthly average rate smooths the volatility but lags real time movements. A defined trading day each month, such as the last business day, is a workable middle ground that is both verifiable and predictable.

The disciplined buyer also defines a dispute mechanism for the rate. If the buyer's auditor produces a different rate from the same published source, the TSA should specify the tie breaker. Usually the tie breaker is a third source agreed in advance. Without a tie breaker, rate disputes drag on and damage the operating relationship. The pattern of structured dispute resolution is in TSA dispute resolution process.

Practical clauses that hold up.

A workable currency clause covers five points. The billing currency, named precisely. The source currency of the underlying cost, where it differs from the billing currency. The reference rate source, including the publication and the trading day. The reset frequency, including the date by which the new rate applies. And the dispute mechanism, including the tie breaker source.

Hedging is a related but separate topic. Some TSAs allow either party to hedge, some require hedging through a named bank, and some are silent. The disciplined buyer reads the silence carefully. If the seller hedges and bills at the spot rate, the seller captures the hedge spread. If the seller hedges and bills at the hedged rate, the buyer benefits or loses with the hedge. The clause should specify whether hedging is permitted and who keeps any hedge gain or loss.

The currency clause is reviewed twice a year through the governance committee. Movements in the underlying rates, changes in the reference rate publication, and shifts in the buyer's currency footprint all justify a refresh. The discipline of structured review keeps the currency clause aligned with the operating reality. The post-signing version of this work is part of TSA renegotiation when the original currency clause has produced sustained margin slippage.

More on TSA negotiation.