The currency circle can also use the "Buffett indicator" to measure bubbles. When the total market value of the crypto market exceeds a certain threshold (such as 15%) of the global GDP, it means that the market valuation is overvalued. For example, in 2021, the total market value once exceeded 3 trillion US dollars, while the global GDP was about 85 trillion US dollars, corresponding to a share of about 3.5%. This rapid expansion is a risk signal. When the mainstream media begins to hype "bull market has no top" and "Bitcoin reaches 1 million US dollars", be cautious. The media hype is usually a reflection of overheated market sentiment and an important signal of peaking.