Women need to "lean in" financially as well as professionally to overcome an inclination to avoid risk, according to a new report that shows men have more money invested in taxable securities, as well as their 401(k)s, IRAs and savings accounts.
The only accounts where women have higher average balances, the report said, are in relatively low-risk money market funds.
Women's reluctance to take risks, and the potential shortfall they face in retirement, have been a growing concern among policymakers and women's advocates. An opinion survey from Prudential insurance company last year found that while some 70 percent of men are willing to take financial risks, fewer than half of women were.
(Read More: More Women Are Breadwinners, But It's Complicated)
But the new report, released by the online rewards program for savings and debt-management SaveUp.com, is based on actual account balances entered by 20,000 of the site's users during the past month, and provides a remarkably clear and up-to-date snapshot of men's and women's financial habits.
The figures are stark and startling. The average man with a savings account had a balance of nearly twice as much as the average woman, and is taking an even greater advantage of high-yield tax-deferred instruments: Men's average IRA balance was 72 percent more than the average woman's, and they have 30 percent more in taxable investments.
"Insufficient market exposure is going to cause a compounding gap over time," said Priya Haji, CEO and co-founder of SaveUp, who follows Facebook COO Sheryl Sandberg's book in advising women to "lean in" on their professional life.