The easiest way to locate an old 401(k) account is by contacting the former employer, explains Henry & Horne, LLP. The person looking for an old plan can review previous statements and try to contact the plan administrator.
It's possible the plan is abandoned, as many are abandoned for a number of reasons, notes the U.S. Department of Labor. If that is the case, the person looking for the plan can search the Department of Labor website, as companies are required to file a Form 5550 annually with the Department. Contact information regarding the plan administrator is on that form.
The person searching for an old 401(k) plan can also check with the National Registry at UnclaimedRetirementBenefits.com, according to Henry & Horne. The former employer may have listed the person searching as a missing participant.