A speculative bubble is a rapid and excessive increase in the price of an asset (real estate, stocks, cryptocurrencies, etc.) due to speculation. Investors quickly buy assets in the hope that their price will rise, allowing them to sell and make a profit. However, this increase is not supported by fundamental factors such as profitability growth or real demand. When investors begin to realize that prices can no longer rise, and demand decreases, a rapid price collapse occurs, and the "bubble" bursts, causing significant losses.