The retail platforms of Fidelity, Schwab, and Merrill Edge do not offer limit-on-close (LOC) orders (I just tried), but IB does offer LOC orders. Suppose an illiquid stock is trading at 10.00 - 10.20. If I place a limit order to buy at 10.10 at 3:58 PM that expires at the end of the day, does that order participate in the closing auction unless someone hits my bid at 10.10 before the close? In general, I am wondering if the ability to place LOC orders is important or if I can get close enough with limit orders placed near the close.