401(k)’s are subject to ERISA laws and pass to the beneficiary and are always exempt from the creditor's reach, both in bankruptcy, from a court judgment, and upon death.. Since ERISA is federal law, Non-ERISA accounts, such as IRA’s, are a different; the rules vary by state. Most, but not all states still exempt these assets from a creditors reach. We can shield additional assets from creditors by use of trusts. You should consult an estate planning attorney to ensure its done properly and legally.
Thankfully no. 401(k) investments are fully protected from creditors so long as the estate is not named as the beneficiary of the 401(k) account. Make sure to check the beneficiary designation of your 401(k) and ensure that someone is specifically named as your beneficiary. Your employer or 401(k) plan administrator should be able to tell you who your beneficiary is. If you have any doubt though, go ahead and complete a new beneficiary designation form just to be sure.
If the beneficiary is someone other than the estate, then no, as it's a payable upon death account and would pass to the beneficiary and not be considered part of the estate. The estate stands good for the debts upon death, so if the 401k is not part of the estate, then the collectors cannot go after it.
Thus, you need to make sure that your beneficiary is named!