Your investment depends on the number of shares (stock ) owned by you. When the company grows, the stock value goes up in the stock market. Your investment is equivalent to the stock value of the particular company.

It is not haraam if you are investing Long term, in that case you are like an owner of the company. If you stay for a month then dip that is haraam. Long term would be considered 2-3 years at least.

Lets say i invest in a company, i give them 10,000 dollars to start up for 20% and in a year the company is worth 1,000,000 so i own 200,000 dollars. Clearly i got more money than i put in. Is that a form of interest? and if not is investing in general haraam? i also do understand it mustn't be a haramm company (selling wines etc)