Since January, the benchmark S&P 500 stock market index has lost about 20% of its value. If you have any stock exposure in your 401(k), your account balance has lost ground, too. And that could mean you need some solid advice on managing your retirement investments in this bear market.

Here's the good news: There are only three basic moves you can make right now in your 401(k), and none of them are complicated. You can do nothing, you can get more conservative, or you can get more aggressive. Read on to decide which option is right for you.

1. Do nothing

Bear markets are temporary. You know this in theory, but it's hard to accept mostly because the timeline is not defined. It might be months or years before the market returns to growth, and that's disconcerting.

Person with eyes closed breathing deeply while standing on the beach.

Image source: Getty Images.

Still, a recovery will eventually materialize. And for that reason, doing nothing is often the best bear-market strategy you can take. Unfortunately, it can also be the hardest strategy. When the market's dropping, you naturally want to do something, anything to regain control.

So your first step here is recognizing that you don't have to follow that urge to act. Lean on whatever life hack normally helps you manage stress -- maybe some deep breathing, a tough workout, or a quiet walk in the woods.

From a calm mindset, it's easier to appreciate the benefits of not reacting to this bear market. Your money stays invested. You don't have to make decisions or predict when the market will turn around. And your portfolio is ready to reap the rewards of recovery gains.

2. Get more conservative

If your intended retirement date is within the next few years, you could reasonably shift to a more conservative investing approach.

To be clear, getting more conservative doesn't have to involve selling off your stock funds. You want to avoid selling now because share prices are temporarily low. You'd get less money in those liquidations as a result.

What you could do is adjust your investment allocations for new contributions. If you're currently investing 70% in stock funds and 30% in bond funds, you could shift to a 50%-50% mix, for example. You might make a big change if your cash reserves are low, or a small change if the goal is to feel more secure about your finances.

A more conservative investing mix won't eliminate the volatility in your account. But it will add to your balance of stable assets. That can be comforting, especially if you're worried about how the downturn affects your retirement timeline.

The drawback of this strategy is that you'll see smaller gains later when the stock market recovers.

3. Get more aggressive

If you don't plan on retiring within the next 10 years, you could increase your retirement contributions for bigger gains later.

Stock prices are low right now because investors are worried about economic headwinds. But there are many good companies that can manage through inflation or recession and come out stronger on the other side. Buying those stocks at today's low share prices can pay off handsomely over the long term.

You can get these stocks into your 401(k) by way of dividend funds that screen for reliability, blue-chip funds, or S&P 500 funds.

This too shall pass

It's stressful to watch your hard-earned 401(k) savings dwindle due to forces outside your control. Know that this downturn will pass.

The market has fallen many times before. And every downturn has given way to a recovery. Have faith that pattern will continue. That mindset will get you through these tough times with a fully invested 401(k) that's poised for some nice recovery gains.