According to a new study, mutual fund investors don’t just tend to buy high and sell low — they also tend to do so shortly before the stock market reverses itself, causing them to get hit by big losses and miss out on big gains.

The study, highlighted by Mark Hulbert in his latest New York Times column, is entitled “Measuring Investor Sentiment With Mutual Fund Flows,” and was performed by two professors and a student at Tel Aviv University.

“The researchers focused on exchanges between equity and fixed-income funds in the same mutual fund family,” writes Hulbert. “In line with previous research on money flows into and out of mutual funds, they found that as the stock market rises, investors tend to transfer money from bond funds to stock funds, and vice versa. They also found something that had escaped notice among researchers: that the stock market tends to reverse itself in the weeks and months after these exchanges.”

The researchers also found that by using mutual fund exchanges as a contrarian market-timing indicator, investors could have increased returns over a 25-year span — and done so while taking on a lot less risk than the broader market.

In addition, they looked at other contrarian-type indicators, and “found that only their indicator had a significant correlation with the stock market’s subsequent return,” Hulbert says. The bottom line, Hulbert says: “Shift money into or out of your stock funds at your own peril. If you still want to try, however, take the opposite path of the average fund investor.”