If a market maker wants to accumulate a large amount of a stock in one trading day, that market maker may actually not report any of the trades that occurred until the trading day has ended so as not to alert the market to the collection. This practice is completely legal under the FINRA rules of the OTC Markets so long as the trade is reported at the end of the day.
To execute a Market on Close” order, a market maker may have an order to purchase the stock
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