In case I trade on a platform like E*Trade or Robinhood and I happen to lose, can I be guaranteed that I will not lose more than my investment? Aka I invest X and I lose X but nothing more. I can afford losing my investment X but I want to avoid getting in debt. I would like to trade on companies like Tesla, Microsoft or indexes like the S&P 500. I would like to trade bullish and also bearish (betting it will go down).
Which investments should I avoid to lose more than my investment?