When you invest in assets from another country, like stocks in Europe or bonds in Japan, you’re not just betting on how well those investments perform. You’re also taking on currency risk, because the value of the euro or yen compared to your home currency (say, the US dollar) can go up or down. Sometimes the currency moves help you, but sometimes they hurt you, completely separate from how your actual investments are doing. 

Currency overlay is a way to manage that risk separately. Instead of adjusting your investment positions every time currencies shift, you use financial tools like forward contracts or options to hedge (protect) or even take advantage of currency movements. Specialized managers often handle this, using strategies that either passively protect against big swings or actively try to boost returns through smart bets on currencies. 

Imagine a US-based pension fund that invests heavily in European stocks. The fund wants the returns from those stocks, but it doesn’t want its performance swinging up and down just because the euro gets stronger or weaker. So, it hires a currency overlay manager.

The manager sets up hedges that offset the euro exposure – meaning even if the euro falls against the dollar, the fund’s returns stay steady. Alternatively, if the manager thinks the euro will strengthen, they might leave some exposure open or even add to it to try to capture extra gains.