點解股票開市時既股價, 會同昨天收市巴股價唔同?

為了一開市時能夠提供開市的恒生指數，其實交易所在 每日 0930 至 0945 已開始盤前交易，目的是開市時前段可釐定公平的開市價，並減低早上開市時大量買賣盤輸入及交易執行訊息對系統造成負荷。
盤前時段分 4 階段，0930 至 0945 為輸入買賣盤時段；0945 至 0950 為對盤前時段；0950 至 0958 為對盤時段；0958 至 1000 為暫停時段。

正如其他人既回答，因為開市前有開市時段，果度決定左當日十點開市時既股價，其實十點開市時，已經做左一次交易，就係開市前時段對左盤既交易。詳細情形可參考以下網址：

http://www.easecurities.com.hk/demo/ordertypes.pdf

because after HK market close, the euro, US market are still running night, and in the morning , japan, taiwan market are start before HK. once these market are affected, HK will be affected too.

The factor normally include the government policy, company news etc..

Thus that why the price are always change, closing price <> opening price

also opening price are decided by the pre-market time 9:30-9:45 the price which have the most transaction in the period, the price is the opening price then.

Hope you understand.