Hedge Effectiveness Testing and the Hedge Ratio

Hedge effectiveness testing is how you prove a hedge actually offsets the risk it's meant to hedge — the evidence that lets you keep hedge accounting. The companion piece explains what hedge accounting is and why it exists; this one drills into the gate you have to pass to use it. Get it wrong and the consequence is concrete: you lose hedge accounting for that relationship, the hedge's gains and losses stop lining up in the P&L with the item they cover, and you get the artificial profit volatility hedge accounting was supposed to remove. In eighteen years of SAP FI and treasury work I've watched effectiveness testing be the quiet difference between a hedge book that reports cleanly and one that generates surprise swings every quarter-end.

(This is a plain explanation of effectiveness testing, not accounting advice for a specific situation — the exact rules live in standards like IFRS 9 and their equivalents, and applying them to your book needs your accountants.)

Why effectiveness matters at all

Hedge accounting is a privilege, not a default. To defer or relocate a hedge's gains and losses so they hit profit together with the hedged item, you have to demonstrate the two really do offset. That demonstration is effectiveness testing. It's the price of admission I described in the companion article: formal inception documentation, plus ongoing evidence that the relationship keeps working.

The stakes are asymmetric. A hedge that's economically sound still fails hedge accounting if you can't evidence the offset — and once it fails, the derivative goes back to being marked to market through P&L on its own timing while the hedged item sits somewhere else. You did the right thing economically and got punished in the reported numbers. That's the outcome effectiveness testing exists to prevent, and it's why treasurers who never touch the accounting still need to understand it.

The hedge ratio

At the centre of the test sits the hedge ratio: the quantity of hedging instrument relative to the quantity of hedged item. Hedge 80 units of a 100-unit exposure and your ratio is 80:100. The rule that matters under current standards is simple to state and easy to get wrong: the ratio must reflect what you actually do to manage the risk. You can't set a ratio to flatter the test — say, deliberately over- or under-hedging on paper to land a number in a comfortable range — if it isn't the ratio your risk management genuinely uses. The hedge ratio is meant to describe reality, not to be tuned for a pass.

IFRS 9: principles, not a bright line

Here's the point people most often get wrong. Under IFRS 9, the standard in force today, there is no mandated 80-125% offset band. IFRS 9 replaced the old quantitative bright line with a principles-based test. A hedge qualifies when three conditions hold:

• there's an economic relationship between the hedging instrument and the hedged item — they move against each other because of the shared risk;
• credit risk does not dominate the value changes arising from that relationship; and
• the hedge ratio reflects the quantities the entity actually uses for risk management.

Notice what's absent: any single number you have to hit. You still often do quantitative work under IFRS 9 — to size ineffectiveness, which still has to be measured and recorded — but passing no longer means landing inside a fixed band.

The old 80-125% bright line

So where does 80-125% come from? It's the strict quantitative test from IAS 39, IFRS 9's predecessor: a hedge was "highly effective" only if offset fell within 80% to 125%. That regime is gone under IFRS, but the number refuses to die, for two reasons. First, habit — a generation of treasury and accounting staff learned "80-125%" as the effectiveness rule and still reach for it reflexively. Second, geography: under US GAAP (ASC 815) a similar bright-line, highly-effective notion has long featured in practice (ASC 815 has since had its own simplifications, but the framing persists). So if you work across IFRS and US GAAP books, or with colleagues who trained under IAS 39, you'll hear 80-125% quoted as gospel. Under IFRS 9 it isn't the rule — treat it as historical and comparative context, not a test you must pass.

Prospective vs retrospective, qualitative vs quantitative

Two distinctions worth one honest line each:

• Prospective vs retrospective. Prospective testing is forward-looking — at inception and thereafter, is the hedge expected to offset? Retrospective testing looks back — did it? IAS 39 demanded both; IFRS 9's forward-looking principles reshaped this, though you still assess the relationship on an ongoing basis and measure realised ineffectiveness.
• Qualitative vs quantitative. A qualitative assessment reasons that terms match closely enough that offset is clear without arithmetic; quantitative methods put a number on it — dollar-offset (compare the value change of instrument and item directly) or regression (test the statistical relationship across scenarios). Simpler hedges can often be argued qualitatively; messier ones need the maths.

Where hedges actually leak: sources of ineffectiveness

Ineffectiveness is any way the instrument and the item fail to move together, and in real projects it's almost always a mismatch:

• Timing — the hedge settles on a different date from the hedged cash flow. The classic: a forward dated to a tidy month-end instead of the actual payment date.
• Notional — the hedged quantity and the instrument's notional don't line up, so part of the exposure is uncovered or the hedge overshoots.
• Index or basis — the instrument references a different rate, index or currency basis from the one the exposure is genuinely priced off, because that index was easier to trade.
• Credit risk — counterparty or own credit changes the instrument's value for reasons that have nothing to do with the hedged risk.

Docs-vs-reality: the documentation describes a clean, perfectly-matched relationship, and the test would sail through — but the actual trade was booked to a convenient date against a standard index, because that's what was liquid the day it was executed. That gap between the documented hedge and the executed one is where I've seen effectiveness testing quietly fail. It's the same discipline the instrument choice demands, and it's why natural hedging — which offsets exposures inside the business with no instrument to mismatch — sidesteps the problem entirely for the exposures it can reach.

Getting it right

Effectiveness testing isn't accounting box-ticking bolted onto treasury — it's the evidence layer that lets a genuinely good hedge report the way it economically behaves. Set the hedge ratio to match what you really do, understand that IFRS 9 asks for an economic relationship rather than a magic number, keep the executed trade honest to the documented one, and measure the ineffectiveness that remains. Do that and the test becomes a formality confirming what's already true. Skip it and you'll meet the volatility hedging was meant to remove. It all sits inside the broader discipline of treasury risk management, where the hedge decision itself always comes first.

Part of the Treasury Risk Management guide. See also hedge accounting explained and FX hedging instruments. The newsletter sends one finance-systems pattern every two weeks.