Henderson, a bank currency strategist, gives you the checklist real trading desks use before publishing a call: four signals that all have to agree. The trend-following rule inside it is the one piece a retail reader can actually test.
The one idea
Henderson's core claim is that no single school of currency analysis works reliably on its own. Classical economic models (Purchasing Power Parity, the monetary approach, the interest rate approach, the balance of payments approach) are useful for multi-year direction but tell you nothing about timing. So he builds a 'signal grid': four independent readings, currency economics, flow analysis, technical analysis, and long-term valuation, each scored buy, sell, or neutral. A trade only gets recommended when all four line up in the same direction.
The book spends its middle third on two specific crisis models built from the 1990s emerging-market blowups: the Classic Emerging Market Currency Crisis (CEMC) model, a five-phase sequence for pegged currencies from capital inflow through collapse to fundamental rally, and a four-phase 'speculative cycle' model for freely floating currencies. Both are diagnostic frameworks for reading where a currency sits in its cycle, not entry systems.
The last third turns practical: how corporate treasuries hedge transaction, translation, and economic risk, and how institutional investors decide whether to hedge at all. The one rule-based, back-tested piece of trading method in the whole book is a trend-following overlay strategy, built from academic work by Lequeux and Acar (1998), that scales a hedge ratio using three moving averages.
What it actually teaches
Henderson's applied method, laid out fully in Chapter 10, has two working parts you can actually replicate: the four-signal grid that gates a trade recommendation, and the tiered moving-average rule that sizes a currency hedge.
SCORE CURRENCY ECONOMICS
Read the balance of payments, the savings-investment identity (S - I = X - M), the Real Effective Exchange Rate versus the external balance, and relative productivity. This gives a buy, sell, or neutral reading, but only on a multi-month horizon; Henderson is explicit that it cannot time an entry.
SCORE FLOW ANALYSIS
Check short-term flow data (the IMM Commitments of Traders report) and medium-term data (US Treasury TIC capital flow report, IMF quarterly emerging-market financing, option risk reversals as a sentiment gauge). Score this signal the same way.
SCORE TECHNICAL ANALYSIS
Support, resistance, and chart patterns on the pair. In the book's worked Turkish lira trade, this leg was a head-and-shoulders top with the neckline at 1.350 million lira per dollar, plus a break of the 55-day moving average.
SCORE LONG-TERM VALUATION
A separate check on PPP, the monetary approach, the interest rate approach, the balance of payments approach, and the portfolio balance approach, distinct from the economics score because it runs on a longer, multi-year window.
REQUIRE ALL FOUR TO AGREE
Henderson's stated rule: only put out an official recommendation when all four signals in the grid read the same direction. He argues this is not a guarantee, but four aligned signals make a materially stronger case than any one alone and should improve realized performance.
SIZE THE HEDGE WITH THE TREND OVERLAY (OPTIONAL)
For hedging or overlay use rather than outright trading, apply the Lequeux and Acar rule: take an equally weighted portfolio of three moving averages, 32, 61, and 117 days. If spot is above all three, hedge the exposure 100%. If it is above two of the three, hedge one-third. In every other case, leave the position unhedged.
What it looks like Monday morning
This is not a system a retail trader takes to a chart Monday morning. It is a discipline for writing down, before you act, whether your fundamental view, your flow read, your chart, and your long-term valuation model actually agree with each other, and refusing to act when they do not. The one piece worth stealing directly is the moving-average hedge scaler: three lengths (32, 61, 117 days), tiered exposure (100% / 33% / 0%) instead of a binary on-off hedge.
The realistic use of this book is as a mental checklist before sizing a discretionary FX position: have you actually checked the balance of payments trend, the flow reports, the chart, and a valuation model, or are you trading off one of the four and calling it conviction.
| Spot vs. moving averages (32d, 61d, 117d) | Hedge ratio |
|---|---|
| Above all three | 100% |
| Above two of three | 33% (one-third) |
| Above one or none | 0% (unhedged) |
This is the book's only fully rule-based, numerically specified strategy; it is built to size a currency hedge, not to generate outright buy or sell trades.
Talk is cheap. The point of this book is to make a difference to the total or relative returns of investors and speculators.Callum Henderson, Currency Strategy
Where it fails
- The one worked trade example is a partial win dressed as validation. The book's single full walkthrough, short USD-TRL from January 10, 2002, hit its 1.350 million target, was held past target, ran to 1.296 million, and was closed for +8.4% including carry. That is one cherry-picked trade from the author's own book of recommendations; he admits elsewhere he has put out calls that lost money, but none of those appear as worked examples. A single winning case study proves the author can pick one good trade to publish, not that the four-signal grid has a real hit rate.
- The signal grid has no stated threshold for disagreement. Henderson says a recommendation should only go out when all four signals agree, but gives no guidance for the much more common case where they do not. His fallback, a risk appetite indicator with three states (risk-seeking, risk-neutral, risk-aversion), is described in half a page with no specific construction method, leaving the reader with a framework that mostly tells you when to do nothing.
- This is a 2002 book about a market structure that has since changed twice over. The book's flow data section relies on the IMM Commitments of Traders report, TIC data, and bank proprietary flow desks as the practitioner's edge. Since 2002, electronic and algorithmic execution, high-frequency market making, and the shift of most spot volume onto ECNs have eroded the information advantage that manual flow-reading gave a bank strategist. The book predates the 2008 financial crisis, the near-zero rate decade that broke carry trade economics for years, and the post-2015 SNB franc shock that changed how practitioners think about tail risk in pegged and quasi-pegged regimes.
- It assumes you are a bank strategist or a corporate treasurer, not an individual trader. The trend-following rule and the differential forward strategy are both described as overlay techniques for a currency manager operating a mandate against a benchmark, with access to forwards, options, and a prime brokerage relationship. A retail trader has no benchmark to trade around and no institutional counterparty to price a seagull or a risk reversal, so two of the book's three concrete rule-based strategies (trend-following, differential forward) are not directly usable outside a fund or treasury desk.
- The CEMC and speculative cycle models are pattern-matched to one decade of crises. Both five-phase and four-phase crisis models are built from the Asian crisis, the Russian default, and the Turkish and Brazilian devaluations of the late 1990s. Henderson presents them as general models for how pegged and floating currencies behave in crisis, but the sample they are drawn from is a handful of correlated emerging-market events in a single macro era of large, mobile cross-border capital flows. He offers no out-of-sample test against crises before or after that period.
Who it is for
Buy it if
You work a currency book professionally, in a corporate treasury, at a bank, or on a fund overlay mandate, and want a structured way to organize the four schools of currency analysis into one recommendation process. It is also useful as a primer on how institutional FX hedging benchmarks and structures (forwards, risk reversals, seagulls) actually get compared.
Skip it if
You are a retail trader looking for an entry and exit system. The only fully specified, testable rule in the book is the 32/61/117-day trend overlay, and even that is framed as a hedge-ratio scaler for a fund, not a standalone trading signal. Skip it if you want position sizing, stop placement, or risk management for a personal trading account.
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