CNN's fear and greed index (Fear & Greed Index), on a scale of 0 to 100, quantifies fear and greed in the market. The higher the score, the more greedy the market sentiment, which needs to sell; the lower the score, the more frightened the market sentiment, and the need to buy.

The index combines seven indicators, each with equal weight:

Stock momentum (Stock Price Momentum):Compare the S & P 500 with its 125-day average.

Stock strength (Stock Price Strength):The New York Stock Exchange touched the ratio of the number of stocks with the highest price in one year to the number of stocks that fell to the highest price in one year.

Stock price trend (Stock Price Breadth):The ratio of upward trend stock trading volume to downtrend stock trading volume.

Ratio of short and long options (Put and Call Options):The ratio of short and long, comparing the trading volume of long options and the trading volume of short options.

Junk bond demand (Junk Bond Demand):The ratio of the yield on investment grade bonds to the yield on junk bonds.

Market volatility (Market Volatility):VIX volatility index

Safe haven demand (Safe Haven Demand):The ratio of returns on stocks to returns on treasury bonds.

Looking back at the trend of the S & P 500 index in the first half of this year, it hit an all-time high at the end of February, fell more than 30% at the end of March, and returned to its previous high at the end of May. This roller coaster is accompanied by great fluctuations in market sentiment.

The fear and greed index was 82 on January 6, indicating that the market is extremely optimistic and confident, and the market is also attacking all the way.

The index quickly fell to 29 on Feb. 25, when the s & p 500 fell more than 3% for two consecutive days.

On March 12, U. S. stocks cut down for the first time, and the fear and greed index fell to an all-time low of 2, indicating that panic in the market has reached its peak.

After the first upward circuit breaker in U. S. stocks on March 26, the mood index rebounded to 18, slightly moderating, but most investors were still on the sidelines.

By May 30, when the S & P 500 came out of a new bull market, the sentiment indicator finally reached the 50 tipping point, indicating that the repair of market sentiment was almost complete.

However, Goldman Sachs Group analysts warned thatThe "unpopular but popular" rebound in the S & P 500 over the past two months is unlikely to be sustained.

Goldman Sachs Group analysts, led by David Kostin, pointed out that after plunging 34 per cent in just 23 trading days, the current rally in US stocks is "unpopular" because investors are not ready to take full advantage of the rebound, but the rebound is "welcome" because most investors are structurally long.