If you are invested in stocks, those holdings will likely see their value fall. But, if you have several years until you need your retirement account money, keep contributing as you may be able to buy many stocks "on sale." Most 401(k) plans have a restricted set of allowed investments, so you likely won't be able to sell short or buy inverse ETFs. Instead, you may want to shift some stock holdings into bonds or money market funds if you are closer to retirement.