For those who don't know, an example of a day trade with stocks would be buying an Apple share for $100 on Tuesday and selling it for $110 on Tuesday (same day). This obviously risks losing money since the Apple share price may go down to $90, for example, meaning the trader would lose $10 for each share he bought. Successful traders tend to make a LOT of money.
Assuming your partner is a successful trader, what would your parents think of him at first?

Feel free to mention what YOU would think about him too
What Girls Said
I would never get into a relationship with a person that takes such risks and I am sure my parents would back me up. Gambling with money has never been a strong point in y family.
However, if that should be the case as per your scenario, my parents would make sure that I would never allow my new partner to have any access to my bank account and that I do not loan him any money whatsoever.
It is so easy to play with other people's money and I would not want to lose a cent or penny on risky trading business just like I would never invest in cryptocurrencies.