Some people without a formal education make it in business, but they're cunning and street smart and have a natural ability with numbers. Business contracts and business deals hinge upon legalities, and if you run across an unscrupulous player, you could wind up losing everything overnight. The stock market is extremely complex. You can borrow money to invest in a business, but you need a business plan to convince a banker. If you don't want to stay in high school, do yourself a favor and take business classes (accounting would also be very useful).
Some people do well in sales, and you could try auto sales. Most self made millionaires got that way through real estate. You need a license for real estate, and maybe a HS diploma. Do some research before you drop out of school. Lots of hard working people get nowhere despite their strenuous efforts.