The Hong Kong Stock Exchange (HKSE) has this rule for limit orders https://en.wikipedia.org/wiki/Hong_Kong_Stock_Exchange#Trading_characteristics Does this mean limit orders sent shortly before the market closes, or does it mean throughout the whole day? What about GTC limit orders? See also https://en.wikipedia.org/wiki/Tick_size
Yeah, I too am trying to understand. I guess to prevent manipulation of the closing price at market close, since the closing price serves also in other "measurements" etc., ie. is an important value that should not be manipulated with mass orders shortly before market close... But I could be wrong... Maybe someone else can say more about it.