我亦認同從交易入手應該較入侵上證電腦系統容易，且是合法—當然，合法與否大內地有多重要是個疑問。因為以交易操控指數很著重最後一分鐘甚至最後一秒內的交易，我個人認為高速交易基金的嫌疑最大，畢竟它們的日常工作就是作超短線的交易控制。
I agree it is probably easier to manipulate Shanghai Composite via transactions instead of hacking. Moreover, the former is legal, though it is doubtful how meaningful this is in Mainland China.
Because manipulation via transaction depends heavily on the transactions in the last minute or even the last second, I personally think high-speed trading funds are the prime suspects. After all, their daily business concerns making transactions in ultra-short time frames to begin with.