New research shows men tend to be overly confident, reactive, and eager for short-term gains when investing money in the stock market, while women are more risk averse. "The latest data comes from Vanguard, the mutual fund company. Among 2.7 million people with I.R.A.’s at the company, it found that during the financial crisis of 2008 and 2009, men were much more likely than women to sell their shares at stock market lows. Those sales presumably meant big losses — and missing the start of the market rally that began a year ago. Male investors, as a group, appear to be overconfident, said John Ameriks, head of Vanguard Investment Counseling and Research and a co-author of the study. 'There’s been a lot of academic research suggesting that men think they know what they’re doing, even when they really don’t know what they’re doing,' he said. Women, on the other hand, appear more likely to acknowledge when they don’t know something — like the direction of the stock market or of the price of a stock or a bond. Staying the course and minimizing costs — selling high and buying low, if you trade at all — are the classic characteristics of good long-term, buy-and-hold investors. But during the financial crisis, the Vanguard study showed, men were more likely than women to trade — and to do so at the wrong times."