I'm a profitable automated stock trader. I've been supporting myself trading for 5+ years, averaging 40% annual returns. I'm active on the algotrading subreddit, and was contacted by the investment arm of a wealthy family last year. I've been trading a small amount of money for them, and they are happy and ready to ramp things up.

They just offered me a job with a base salary plus profit share, they want me to head an internal hedge fund (low 7 figures to start) and build a track record for a year, then they will raise the capital invested. I would also be in charge of hiring and heading a team. This position requires an overseas move.

I've spent ~10 years writing my trading codebase (70,000 LOC), along with extensive backtesting resulting in roughly 10 different profitable patterns (systems) that I trade. I want to protect myself and that IP.

I want to say that there haven't been any red flags in this process. I've met several of their people, multiple times, and they are excited and want a long-term relationship. They've looked for a person like myself for this project for a while, and recognize my expertise.

They are a bit naive in the coding/tech domain (their family money is in mining and real estate). They just sent me a (boilerplate) contract which gives them rights to any property "developed in the course of the engagement" along with property "relating to the Proprietary Property."

I am fine with giving them access to anything I develop while being paid by them, but it will be tough to separate from my existing codebase and systems, which I will use to trade their money, presumably on their server. (I lease my own VPS now, and their brokerage account is connected to mine via an advisor account.)

I'm excited for the chance to run this fund, but am a bit overwhelmed by potential legal and financial missteps.

TL;DR: Has anyone ever been in a situation where they needed to use old code for a new employer, without relinquishing IP rights?