In the early days of legalization, marijuana stocks were limited to OTC exchanges, with the lack of public acceptance and funding leading to banking issues. Today, you can invest in weed stocks on most major U.S. exchanges. For example, Canadian-based cannabis products producer Aurora Cannabis (NYSE: ACB) exists on the NYSE. At the same time, you'll need access to the NASDAQ to invest in cannabinoid company The Cronos Group (NASDAQ: CRON).