As far as I know, or have heard from my broker, there is no "guarantee" that the entire quantity will get filled in one trading day. That's how I got raped long ago, one time. I guess all that was "available" during that day, and at my limit price, was 30 lousy shares. So as I understand it, you open the door to such "partial" trades, as soon as you chose something other than "all or none".........Believe me, I wish there was a "safe" method, of slowly filling an order(or accumulating) over a prolonged period of days or weeks.........The only way I believe some traders can accomplish that, is to have "unlimited free trades", due to either an enormous balance in the account, or a large annual account "fee". I think one could accomplish it, with what I see sometimes in opening a new account with some brokers, where they give you X free trades to start out, or all trades are free for the first month, etc..........
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