Workers may see losses in a bankruptcy if they invested much of their retirement money in their employer’s stock or if the employer made matching contributions in company stock, Mr. Stein of the Pension Rights Center said. Employees usually have the right to diversify their investments out of their company’s stock, he said, but they often don’t, in part because familiarity with their employer may make them overconfident in the stock.

“The most important step someone can take when a company is in turmoil is to update their contact information with the plan,” said Anna-Marie Tabor, a visiting professor at the University of Massachusetts School of Law. If you don’t get updates, you may not know that you have to take action. If you take a new job and leave your 401(k) behind at your old employer, make sure you continue to update your contact information — and if you don’t hear from the plan for a while, get in touch to find out why.

If you are having trouble getting information about your retirement plan, or you suspect that contributions have not been properly deposited in your retirement account, you can contact the Employee Benefits Security Administration, part of the Department of Labor, at askebsa.dol.gov or 1-866-444-3272. That is what the Labor Department suggested that former Bed Bath & Beyond workers do.

It can be expensive to hire legal help, especially if the amount of money in question isn’t large. Groups like the Pension Rights Center and the Pension Action Center may offer free legal advice or referrals for people with concerns about access to their retirement plans.

If you don’t have it already, ask the company for a copy of a summary plan description, which explains details of your retirement plan, including vesting schedules and contact information, said Maria C. O’Brien, a professor at Boston University School of Law who specializes in employee benefits and insurance law. You can also contact the Department of Labor, which may have copies of the document.

Employees should also read the prospectus, or disclosure, for any investment option they will be using, Ms. Costa said. But even if people do request the documents, she said, “they aren’t exactly light reading.” Words like “guaranteed” in the name of an investment suggest a lack of risk, she said, but guarantees come with conditions, such as a specific period for which an investment must be held.