The cumulative position ratio of the main tracking of Tongda letter reached 1.74%. Please refer to the following formula. Through practical exploration, we can measure the main positions through the internal statistics of real-time transactions. Formula 1: The main buying amount of the day =(× 1/2+ internal market ×110) ÷ 2, and then accumulated for several days. According to the author's experience, at least the turnover rate reaches 100% to stop tracking. Generally, 60 to 120 trading days is appropriate. Because the opening period of a main band is usually about 55 days. This formula requires investors to tirelessly analyze the target stock every day, so the error rate is very small. Multiplying the daily turnover of the bottom cycle by the empirical parameters can roughly estimate the main positions. Formula 2: Main positions = total turnover at each stage (refer to the condition of formula 1) × (empirically estimated as 1/3 or 1/4). For the sake of caution, you can confirm the low position, that is, you can use the result of 1/4.