In recent weeks, the US yield curve has been making investors nervous again. The curve has inverted before each of the last seven recessions, and it did so again on March 22. But what does an inversion really mean for equity returns?

The yield curve simply tracks how long-term interest rates stack up to short-term rates, and it’s said to invert when short-term rates are higher than long-term ones. After three-month Treasury bill rates topped those of 10-year Treasury yields for the first time since 2006, we took a closer look at what happened to equity returns after the 11 other inversions that have occurred since the 1960s.

In the very short term, the effect of an inversion is negative. In recent years, that may be because the yield curve has gained incredible power in the minds of financial market participants as a foolproof signal of impending recession. In other words, the signal itself, rather than any fundamental conditions it signifies, might make investors nervous. In earlier years, when yield-curve inversions didn’t even warrant a mention in the New York Times, concern over how rising short-term interest rates would affect loan conditions seemed to be more top of mind.

However, average stock returns were negative only in the first month after an inversion. Further out, average returns were positive. And the more time that elapsed since the inversion, the more positive the average returns were.

Looking more closely at long-term trends, however, the picture is more nuanced. Three months after an inversion, stock investors booked positive returns nearly three-quarters of the time. But by the time a year had passed, the results were usually much more extreme: either very positive or very negative.