11.5 Close of trade with closing auction
1 Immediately before close of trading, an auction is conducted in accordance with the principle of highest executable volume. If there is a trade in the auction, this price shall be the closing price and the new reference price. If there is no trade in the auction, the last trade of the day shall be the closing price. If there is no trade during the day, there shall be no new closing price and the existing reference price shall remain unchanged.
2 The Exchange may adjust the reference price in certain cases.