This wouldn't be 25% of your profit, it's just increasing one of your expenses by 25%. ~~It looks like it's going up to $3000.~~
Edit: Enterprise price is negotiated with each company, so there's not a set subscription price. But it's still just the price of one expense, not a portion of total profits.
In the US, brokerage companies legally have to send you a Form 1099 which covers all investment income over the year. You then include this when submitting your taxes. They probably send a similar report to your government instead.