Start with what actually happened to FX markets in the lead-up to April: there was a geopolitical shock and oil supply out of the Middle East came under pressure. The immediate reaction across currency markets was the one traders have seen before: money moved toward safety, toward yield, and away from anything that looked exposed to the disruption.
Safe-haven flows meet yield divergence
The US dollar benefited from both of those forces at once. It is a safe haven and it also carries a yield advantage that most of its peers cannot match right now. The Swiss franc picked up some of the overflow from European risk aversion. The yen, which used to attract safe-haven flows almost automatically, is stuck in a different situation altogether where the yield gap against the dollar is now so wide that safe-haven logic has been overridden by carry logic.
The currencies that had the toughest month were the ones caught in the middle: risk-sensitive, commodity-linked, or running policy rates that simply cannot compete. The New Zealand dollar is the clearest example while the Australian dollar is a messier story. Sitting underneath all of it is a repricing of 2026 rate cut expectations that central banks in multiple countries are now reassessing.
Strongest mover: US dollar (USD)
The US dollar spent most of 2025 gradually losing ground as the Fed cut rates and the rest of the world played catch-up. That story stalled hard in late March. The Iran conflict changed the calculus, and the dollar reasserted itself in a way that reflects something real about its structural position in global markets.
The US exports oil and when energy prices rise, that is a terms-of-trade improvement, not a terms-of-trade shock. Most of the dollar's major peers sit on the other side of that equation. Add a policy rate range of 3.50% to 3.75% that now looks locked in for longer, and the dollar's advantage is both cyclical and structural at the same time. The US Dollar Index (DXY) has regained the 100 level but tThe question heading into April is whether it holds there or pushes further.
Weakest mover: New Zealand dollar (NZD)
If you wanted to design a currency that would struggle in the current environment, the NZD fits the brief almost perfectly. It is risk-sensitive. It is commodity-linked. It runs a policy rate of 2.25%, which sits below the Fed and now below the RBA as well. New Zealand is also an energy importer, so rising oil prices hit the trade balance and the domestic inflation outlook at the same time.
None of those things are new but the combination of all of them hitting at once, against a backdrop of a surging dollar and broad risk-off sentiment, has compressed the NZD in a way that is hard to ignore. The carry trade that once made NZD attractive has reversed as capital has been moving out, not in.
USD/JPY
USD/JPY is the pair that most clearly illustrates what happens when a currency's safe-haven status gets overridden by carry logic. The yen used to be the first port of call for traders looking for protection during geopolitical stress. That dynamic has been suppressed, and the reason is straightforward: you give up too much yield to hold yen right now.
The Bank of Japan (BOJ) policy rate sits at 0.75% while the Fed's sits at 3.50% to 3.75% and that gap does not encourage safe-haven flows. It encourages borrowing in yen and deploying elsewhere. So while the dollar rose on geopolitical risk, the yen fell on the same event. That is not how it is supposed to work, but it is how the maths works out when yield differentials are this wide.
USD/JPY is sitting near 159, which leaves it not far from the 160 level that Japan's Ministry of Finance has consistently flagged as a line requiring attention. The BOJ meeting on 27 and 28 April is now a genuinely live event.
Data to watch next
Four events stand out as the clearest potential FX catalysts in the weeks ahead. Each has a direct transmission channel into rate expectations, and rate expectations are driving much of the move in FX right now.
Key levels and signals
These are the reference points that traders and policymakers are watching most closely. Each one represents a potential trigger for a shift in positioning or an official response.








