The Fear and Greed Index is a tool for measuring the market sentiment of Bitcoin investors. This overall feeling of investors towards market conditions is also known as market sentiment. The index ranges from 0 to 100, where 0 represents extreme fear and 100 represents extreme greed. Within this range, the index is divided into four basic categories: 0 to 24 = Extreme Fear, 25 to 49 = Fear, 50 to 74 = Greed, and 75 to 100 = Extreme Greed.

If 75% of the Top 50 coins performed better than Bitcoin over the last season (90 days) it is Altcoin Season