I recently came across an article which said the following:
" Order matching in most [exchanges] is done on the basis of price-time priority. When a new order is placed in the exchange, best buy order (highest price) is matched with the best sell order (lowest price). Price level matching will get more priority to execute the trade. If the prices quoted are the same and both the orders are the same type (buy/sell), then whoever has placed the order earlier will have the higher priority while the orders are filled. Hence order matching is based on price-time priority. Further, if time and price are same (almost impossible assuming high granularity of time and other measures that are implemented), some exchanges mandate that the larger order gets filled first. And if all the conditions are same, the orders matched are filled based on pro-rata basis i.e. the shares are split among the orders. Hence, an order may end up in one of three states; Filled, Unfilled, and Partially filled."
Hence I wanted to know, that in a pre market session, if the time of orders is same (just assume for now, regardless of possibility it), then in that case, Does BOMBAY STOCK EXCHANGE (BSE) and/or NATIONAL STOCK EXCHANGE (NSE) mandate “PRO RATA BASIS” execution? (note: in this specific situation only, I know its price/time otherwise)