My Comments: You say you don’t have a 401(k)? Maybe you have a 403(b), or an IRA with exposure to the market. If you are in or close to retirement and your investment portfolio goes to hell, you simply don’t have enough time to hope it recovers and gets back on track. Be defensive for a while and sleep better at night.

by Carolyn Bigda | September 26, 2016

Storm clouds are forming, so take your nest egg off autopilot and steer to clearer skies.

Blissfully, making your 401(k) grow hasn’t been that hard in recent years. Since March 2009, the S&P 500 index of U.S. stocks has more than tripled in value. And thanks to the Pension Protection Act—now celebrating its 10th anniversary—many workers are automatically enrolled in 401(k)s. “Inertia has led to some pretty powerful results,” says Katie Taylor, director of thought leadership at Fidelity.

But inertia works only as long as the winds are blowing in the right direction. Today there are signs that momentum could be shifting. U.S. equities, for one, are as frothy now as they were leading up to the 2007–09 bear market and the Great Depression in 1929. The S&P 500 trades at a price/earnings ratio of 27.3 based on 10 years of averaged profits, a 63% premium to historical averages.

Meanwhile, corporate profits have been declining for five consecutive quarters, the worst such streak since the financial panic. And worried fund managers have amassed large piles of cash, according to a recent Bank of America Merrill Lynch survey.

None of this means your 401(k) needs a major overhaul. This is, after all, your long-term portfolio, meant to endure choppy air from time to time. But a few tweaks now can help ensure that inertia doesn’t work against you—and that you’re still on track no matter what happens in the market.

Get over your fear of bonds

If you haven’t rebalanced your 401(k) in a while, it probably looks different from what you remember. Without rebalancing, a moderate 60% U.S. stock/40% U.S. bond portfolio at the end of the last recession is now closer to an aggressive 80% equities/20% bond mix, according to Morningstar.

The rule of thumb: If your weightings are off-kilter by five percentage points or more from your desired mix, it’s time to take action.

Some investors, though, may be wary of rebalancing into bonds now, notes Maria Bruno, a senior investment analyst in Vanguard’s investment strategy group. That’s in part because fixed-income prices fall when interest rates rise, and the Federal Reserve could lift rates before the year is out.

But “rebalancing helps protect you from short-term volatility,” Bruno notes. Even if fixed-income prices fall, bonds can still serve as a cushion. The worst calendar-year loss for intermediate-term government bonds was 5.1%, in 1994. By contrast, the worst loss for blue-chip U.S. stocks was 43.3%, in 1931.

You can further reduce risk by choosing bond funds with an average “duration” of about five years or less, which are less sensitive to interest-rate moves, says Peter Mallouk, president of Creative Planning in Leawood, Kans. (A duration of five implies that if rates rise one percentage point, the fund could lose 5% in value.) You can look up this figure for your plan’s fixed-income offerings at Morningstar.com. If your 401(k) doesn’t offer a good low-duration option, go with a core fund such as Dodge & Cox Income DODIX 0% , with a duration of just four years, in your IRA. The fund, which has beaten more than 80% of its peers over the past five, 10, and 15 years, is in our MONEY 50 recommended list.