NEW YORK (CNN/Money) - I have $10,000 in my 401(k) plan at work that is 100 percent invested in my employer's stock. If my company pulls an Enron, I could lose everything. Since I'm fully vested in both my own and my employer's contributions, should I rollover to an IRA?

-- Laura, Hoboken, New Jersey

You're right to be concerned about getting "Enronized" by holding such a large percentage of your 401(k) in your company's stock. Generally, I think it's a bad idea to keep more than 10 percent of one's retirement savings in an employer's stock, or any single stock for that matter.

That's not to say there aren't exceptions to this guideline. You could justify holding a higher percentage if you've got a large well-diversified portfolio outside your 401(k) plan, or if you're simply willing to take on a much higher level of risk for a shot at higher returns (though the Enron saga shows how truly difficult it can be to gauge risk vs. reward).

But I find it hard to envision any reasonable scenario where it makes sense for you to hold 100 percent of your 401(k) in company stocks.

The question, then, is what to do about it. Your solution of rolling your 401(k) money into a rollover IRA would be a good one, if you were able to do it. Unfortunately, regardless of whether you're fully vested or not, such rollovers are only allowed when you leave a company to retire or switch to another job.

As long as you're still employed there, you can't withdraw your 401(k) money and move it elsewhere. Other than borrowing or taking a hardship withdrawal -- which wouldn't help much in this case -- your money is pretty much stuck in the plan.

But there are other moves you can make. First of all, if every cent of your money is in your employer's stock, then that must mean that not just your employer's match, but your own contributions are being invested in company stock.

I would think that you do have the ability to channel your own contributions to other investments. These days virtually all 401(k) plans offer a menu of investing options outside of company stock. So the first thing you should do is see what other options are available for the money you contribute to the plan, and then start moving your past and ongoing contributions to other investments.

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The second thing you should do is see if there's any leeway in moving your employer's matching contributions. After the Enron debacle, a number of companies that had previously prohibited employees from moving company matching funds out of company stock began to relent in a variety of ways.

Some just allowed people to move the money at will. Others allowed them to move matching contributions that had been in the account a minimum period of time, say, three years. (Companies typically allow employees to begin diversifying out of company stock as they approach retirement age. But if retirement is way off, that's not much help.)

So check with your human resources department and confirm what the policy is at your company when it comes to moving matching funds. If your employer still forces you to keep the match in company stock for a long time, you might band together with other employees and ask the company to change the policy.

Finally, if despite your best efforts you find yourself faced with having to hold a big slug of company stock in your 401(k), you should at least take some moves to diversify around that position as best you can. For example, if you work for a tech company, then maybe you could tilt the rest of your portfolio less toward growth stocks and more toward value. Throwing in more bonds than you would normally hold isn't a bad idea either.

For more on how to diversify around a position of company stock both within and outside your 401(k), click here. And you might also check out the RiskGrades Web site. There, you can plug in the holdings in your 401(k) -- which shouldn't be very difficult or time consuming for you -- and get a RiskGrade, which is a proprietary risk measure based on an investment's volatility compared with that of a basket of global equities. In other words, you get to compare the riskiness of your 401(k) with that of a diversified portfolio.

What's more, you can then plug in other investments that you can invest in both inside and outside your 401(k) -- stocks, bonds, mutual funds, whatever -- to see how adding different investments in various proportions can lower the risk profile of your retirement holdings overall.

Even if the moves you can make are limited, by going through this exercise you'll at least be able to see which moves are likely to provide the biggest reduction in risk.

Walter Updegrave is a senior editor at MONEY Magazine and is the author of "Investing for the Financially Challenged."