No more than 10 percent of your portfolio should be in any one investment, including the stock of the firm you work for, says Chris Cordaro, chief investment officer for RegentAtlantic Capital, a wealth-management firm.
So give yourself a target and a timetable, start shedding company stock and reallocate the cash into a diversified fund.
Chances are, you can begin unloading employer shares right away. Under a 2006 law, firms that match a 401(k) with company stock must let you sell it once you've worked there for three years.
If you have to wait, keep the rest of your money in funds that don't list your company among their top holdings (to check, go to morningstar.com). And don't compound your risk by buying ETFs or sector funds in your own industry.