ST Trading discussion, page-233

If you're trying to do solid numbers look at it from a cash invested / cash return basis. You invest X to start your company, your company returns Y amount of revenue which equals Z amount of return per month / per quarter / annually etc therefore investors see the return % and inturn decide how desirable the stock/company is and possibility for dividends/capital growth which inturn affects the SP in both a calculated and emotional way.

Do your research on the company/directors/market strategy/business strategy/possibilites to growth/demand for tech etc etc -due diligence... then... Decide if the stock is worth purchasing and then decide how much risk/capital can you invest. Boom Investing 101.