The S & P 500 has risen 54% in the past 102 trading days, the biggest gain in the same period, and is gradually approaching its record high. This makes investors think: < / P > < p > Reuters strategist April Joyner pointed out on Monday that as major stock indexes approach historical highs, the 5-day moving average of the P / C ratio (the ratio of open positions of put and call options) of the S & P 500 index shows that: < / P > < p > “whether the S & P 500 is followed by a near perfect double top or a new high, this indicator seems to mean that the market may soon face instability.”. < p > < p > with the S & P 500 index breaking through February’s record closing high of 3386.15 on Tuesday, it rose to 3387.85, the 5-day moving average of P / C ratio. From the perspective of reverse investment, this implies that the market is too optimistic or complacent, and it is easy to reverse. < / P > < p > since the end of 2018, when the S & P 500 index reaches an important level, the reading of the index is often lower than 0.60. In fact, at the beginning of June this year, when the index fell to a 20-year low of 0.402, the S & P 500 index quickly fell more than 8% from its high in just five trading days. < / P > < p > that is to say, the higher the closing price of the S & P 500 index, the higher the bottom of P / C ratio is than the 5-day average before the two most drastic falls of the S & P 500 index in late 2018 and early 2020. After hitting the bottom in early June, the index formed a higher bottom in mid July. Now, it seems to have reached a second higher low this month. Meanwhile, the S & P 500 continued to rise. As a result, Joyner once again stressed his view: with the S & P 500 index successfully breaking through its February high, whether the next step is to form a near perfect double top or a new high, the P / C index seems to mean that the market is likely to have a huge shock soon. In this regard, the financial blog zero hedging said that although the hope of successful vaccine research and development and the increase of global liquidity have prompted the market to rebound to a near historical high, many factors indicate that the market is still full of many imminent dangers, including the possible reversal of the country’s re opening up, the economic recovery trend from “V” type to Nike’s “√” type, and more serious The budget deficit and debt burden, and the cliche of overvaluation.