Looking forward to retirement as a time to start that business you’ve always known you could run? Be wary of using your retirement money as seed money, lest its pros turn into cons.

According to a NerdWallet report, while there’s a retirement account option for launching a business—known as a Rollover for Business Startups, or ROBS—there are reasons to be very careful if you take this route to entrepreneurdom. Says the report, “While this type of financing can provide you with money to fund your business, the complex transaction doesn’t make sense for everyone.”

You can use funds from eligible retirement accounts, including a 401(k) or a traditional individual retirement account, to launch a business. The accounts get rolled over (usually with help from an attorney or a ROBS provider) so that you can use the funds either to invest in a new business or franchise or even buy or put money into an existing business.