How Are Stock Prices Manipulated?

In recent years, our country

In China's stock market, individual investors account for 99.5%, institutional investors account for 0.5%, and actors are individual investors.

However, the amount of capital owned by institutional investors is large, which is the trend of the market.

In addition, China's stock market shares account for only 1/3, and the average circulation market value is very low, which provides convenience for institutional investors with capital advantage to manipulate stock prices.

In addition to capital advantages, institutional investors also have information superiority and can even manipulate stock prices by using insider information.

The results of our empirical study are as follows:

First,

(1) buying and selling oneself.

We examined the number of buying and selling pactions and trading shares of 19 stocks in 1999-2000 years' participation in trading shareholders. The results are shown in Table 1 and table 2.

Judging from table 1, only one close to 50% from self purchase paction occurred, 2-3 times close to 20%, 4 times more than 30%.

It is undeniable that most pactions belong to the banker's behavior.

From table 2, part of the buying and selling pactions are very few, and the number of pactions is less than 100 shares, accounting for 10%. Some of the shares are sold by themselves, and the number of pactions is more than 10000 shares, accounting for about 25% of the total volume of pactions.

From the irrational paction of self purchase and self selling, traces of the dealer can be found.

Since July 1, 1999, the securities law has been implemented, and the behavior of shareholders buying and selling themselves should be convergent. Figure 1 shows the number of self buying and selling each month in 1999-2000 years.

We see from Figure 1 that after the implementation of the Securities Act, the self purchase behavior did not immediately converge. In 2000, the 6 contract was 4650 times more than the record, and the number of trading stocks was 21 million 620 thousand.

Since July 2000, the phenomenon of self purchase has been greatly reduced, and the number of pactions is mostly below 100 times. The number of trading stocks is mostly below 10 thousand shares.

We calculated the number of shareholders and the number of shares that each stock involved in buying and selling itself. The average number of shareholders is 29, the median is 25, the maximum value is 138, the minimum value is 10, the average number of shares traded is 597 thousand shares, the median is 389 thousand shares, the maximum value is 3 million 625 thousand shares, and the minimum value is 40 thousand shares.

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(2) repeated pactions

Since the buying and selling pactions are easy to reveal, the dealer uses more account pactions to manipulate the stock price. Table 3 gives the statistical results of the number of pactions between accounts over 2 times.

From table 3, in the 423701 repeated pactions, nearly 70% have been repeated 2 times, 3-4 times 20%, and 10% times more than 5 times.

There may be repeated pactions between two unrelated shareholders, but not too many.

The greater the number of repeated pactions between the two shareholders, the greater the correlation.

We calculated the number of shareholders who traded 6 times or more per stock, with an average of 1046, a median of 990, a maximum of 2128, and a minimum of 234.

From the disclosed case, there are about hundreds of shareholder accounts used by a dealer to manipulate a stock. If the number of accounts is too small, the stock is relatively concentrated and easy to be exposed. If the amount of accounts is too large, the operation will be cumbersome and unnecessary.

We take the 6 time as the critical value, and accounts for more than 6 times may be the banker.

(3) intra day irrational pactions

We calculated the number of low and high purchase accounts in each stock day, with an average of 2495, a median of 1977, a maximum of 6148, and a minimum of 269.

But it is not necessarily the dealer who makes such a paction. For example, when an investor sells shares, he finds that the stock price continues to rise, resulting in regret.

But in order to manipulate the stock price, the dealer often deliberately adopts such irrational paction. Therefore, it may be the dealer who takes this kind of behavior.

(4) pfer of custody

Repeated escrow is one of the commonly used means of banker.

We calculated the number of accounts pferred to each trust stock, with an average of 4499, a median of 3177, a maximum of 13135, and a minimum of 1173.

(5) makers' judgement

Based on the above research, we attribute the characteristics of the banker to self purchase, self sale, repeated pactions between accounts 6 times, irrational trading within the day, more than two times of trusteeship, the top 1000 cumulative pactions and the top 1000 positions.

We regard the above 2 characteristics as the banker. The average number of the banker is 920, the median is 959, the maximum is 1285, and the minimum is 563.

Generally speaking, there are hundreds of accounts used by a dealer to manipulate a stock, and the above results are in common sense.