Conceptually Bitcoin is a “Capital Asset”. When a capital asset depreciates in value, it's called a “Capital Loss”. Again, until and unless you actually sell the Bitcoins, the loss is considered “unrealized”. Such a situation has happened a couple of times when stabilization of the crypto is cleaning the mess that is circulating in the market. In every case that Bitcoin has depreciated, it has not decreased so much and soon after lowering its price it had rapid growth after that. When next phase of decreasing will begin some will keep the BTC cause they learned that after every fall there comes the growth. But the best way to trade would be when BTC is in a growing phase. It’s like if you bought a bitcoin for $5000, and someone comes up to you and offers me $4500 for it, you haven't lost $500 unless you sell it to him. So, hold on to that bitcoin at that point in time.