An emploiyee often signs only an employment contract before they are in the first day of their employment. A contract says that an "emplyee handbook" is a part of teh contract but the employee may or may not receive this huge (sometomes 500 pages) document before they actually start. You can't blame a person for not reading about "griefing procedures" when they don't have anything to relate these to. To the OP: Owning a part of a business (which in the present is almost necessarily equity stocks) is a fundamental human right and an employer cannot deprive you from this. However, they will likely make it more difficult to excercise. In the extreme case you may be: 1) Prohibited from anything that may carry risk of you loosing more than the value of the trading account: shorting stocks, buying on margin, trading any kinds of derivatives (options, futures etc). 2) Prohibited from anything which looks different from investment acvtivity (for example, owning a stock for less than 15 days) 3) Required to obtain a permission from a compliance officer to buy/sell any stock on the day you execute a transaction 4) Required to execute trades exclusively through the firm's brokerage (assuming they own one). I think the easiest way to sort out your dobt is to mention to whoever is your contact in the company that yopu own a few stocks and want to find out about their compliance policy. They may either send you a compliance manual or arrange a 5-minute telephone call with a compliance officer.
You can only trade/invest through the B/D of their choice, and then the trades have to be approved one by one. If they are covering a certain stock or instrument, you likely will not be allowed to place a trade. Additionally, those chosen B/Ds often have rip-off commissions. My advice is to get someone you trust and have then run your prop account, have it in their name. I'm not sure if it can be your father or mother, but it's not like you're going to be investigated. You have to show no ties to the trading. If your system has no live results and it's all simulated backtested data, I would say do not even waste your time. Focus on your internship instead, work on the system but don't set it live. Because your perceived $125 a day is most likely just a dream. I'm going by US rules, btw.
You are risking a real job for an strategy that you THINK will make you only $125 per day ($15.63 per hour on a 8 hour shift)??? You think the strategy will be profitable, yet surprises happen. Even if it was profitable in the past there's no guarantee it will continue to do so. Definitely bring the subject with your boss, if he tells you you should quit trading do so. Jobs are scarce, there are thousands of people waiting for your job.