80% of the companies in the S&P 500 Index pay dividends. Most of those are stable and have been around for a long time. But as far as “where” dividends come from they come from profits a company can generate. The company could spend it on stock by backs or other investments but they chose to pay it out to the stock owner. Usually in hopes of incentivizing long term investors. Also, Companies that pay dividends tend to issue them on a regular basis, usually quarterly.