7日烧碱下跌2.90%，最新持仓变化

Group 1 - The core viewpoint of the article indicates that as of August 7, 2025, the main contract for caustic soda (2509) experienced a decrease of 2.90%, with a trading volume of 220,600 contracts and a net short position of 20,023 contracts among the top 20 positions [1][2] - The total trading volume for all caustic soda contracts reached 401,300 contracts, an increase of 6,080 contracts compared to the previous day [1][3] - Among the top 20 positions, long positions totaled 188,900 contracts, an increase of 4,724 contracts, while short positions totaled 214,200 contracts, an increase of 7,350 contracts [1][4] Group 2 - The top three long positions were held by Guotai Junan with a total position of 21,089 contracts, Dongzheng Futures with 18,231 contracts, and CITIC Jiantou with 17,521 contracts [1][3] - The top three short positions were also held by Guotai Junan with 31,337 contracts, Dongzheng Futures with 22,827 contracts, and CITIC Futures with 20,855 contracts [1][4] - The article provides detailed data on the changes in positions for various futures companies, highlighting significant increases and decreases in both long and short positions [1][3][4]