Not a lawyer, but have navigated IP partitioning with big engineering firms for over two decades. General answer to you question is "no", but the truth of cours

Not a lawyer, but have navigated IP partitioning with big engineering firms for over two decades. General answer to you question is "no", but the truth of course is that it depends on when and how you've protected your IP, and what country your in. If you're in the USA and you patent a technology, then join a company, the company doesn't have a claim to that technology unless you both explicitly agree to it during your onboarding. For example, it's possible a part of the reason a company want to bring you onboard is that they are partly interested in you're IP and partly interested in your ability to develop/implement that technology (the latter being exceedingly more difficult that generating the initial idea). In any event, you may agree to sign over IP rights (fully or partially) in exchange for better compensation. If you don't patent your IP before joining a large company, then you need to review the IP terms before you join, because in general (certainly not always) companies do tend to claim ownership of any IP you create while employed at their company. However, this clause is mostly to protect the company not inhibit your creativity or success, so you can easily get a waiver to keep building and securing IP for your own gain. That's what I did.