If bitcoin value is going down do you lose anything or only when you sell like the stock market? If Bitcoin is going down, do I only lose if I sell my bitcoin?
So, if I hold them I won’t lose?
Well basically, think of it as if u had an apple. If you decide at any moment that you want to sell it, you get a specific price for it, which is the current price of an apple.
So if you bought 1 bitcoin when 1 bitcoin was worth 18K USD and sold it at 27K USD you have now a profit of 50% which means that you now have 27K USD as fiat in your hand instead of having 18K (which you had when you bought a single BTC worth 18K back then)
This works the same if you buy it at 27k and sell it at 18k, except, you then lose 33% of your money that you invested in it when you bought it. That means that if you buy 1 BTC at 27K and sell it at 18K because maybe you are scared to lose more, you end up losing 9K because you sold it.
If you don't sell it, you will remain with that 1 BTC the whole time when it's price fluctuates, but it is basically worth more (or less) depending on it's current market price.