On the 9th of January, while the US markets were closed, I placed a market order on GPRO (nasdaq)

The next day, I noticed that my order was executed at $6.10 at the market opening, 9:30am (ET) precisely. However the charts show the stock went from 6.031 to 6.0596 then 5.9301 respectively in the first three minutes.

My broker's explanation is "Sellers at NASDAQ were positioned at $6.10 at that time"

I am still confused, can a market order be above the market rate ? c.f. screenshot from charts (Time is GMT+1 / Paris)

Thank you.

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  • You got more money, shouldn’t be that confusing but there are a few possibilities.. those charts may not have accurate data or since the order was filled at 9:30 AM EST.. it may have been filled milliseconds before in the premarket which then logged it at 9:30 AM. But just to be clear, someone bought it so someone was willing to pay at that price even though it dropped afterwards. It didn’t happen out of luck or anything.
    – NuWin
    Jan 19 '18 at 3:25
  • Sounds like an odd lot order. How many shares were involved? Jan 19 '18 at 3:56
  • 150 shares, why ? Jan 20 '18 at 4:45

I am not sure specifically about nasdaq; however exchanges that allow overnight market order have a slightly different matching rule.

Market orders have the highest priority. There could be situations specially on overnight market orders where you have one market order match other market order and in such situations a separate price algorithm takes over.

Generally in order to determine fair price and factor in any news after closing of markets, when the exchange opens for trade ... the market orders are kept on hold for initial sometime [5 to 15 mins]. This then gives the direction a specific stock is moving ... this along with previous close price as well as historic value etc all go into a pricing algorithm of exchange [the algorithm is closely guarded secret so that people don't game the market].

After this price is determined, the exchange matches the market orders to other market orders [at the determined price] or to the limit orders at the limit price.


Market opening could be executed with discrete auction mechanics, because there could be volatile start, to make spread less. If your exchange does not employ discrete auction, then your starting volatility and spread will be high, and don't mind if that could be the size of 10-30 cents.

This is the nature of market orders in opening. If you don't like that, avoid using market orders and use limit orders / algorithmic / SL orders etc.

  • 1
    It's not that I don't like. From a learning perspective I like to understand what happened and know if it is to be expected or not. Do you have any supporting documentation or references to these 10-30 cents spread or is it by experience ? Is a market opening spread caped at ~30 cents, or more like 1%: this makes a big difference whether a share for a given stock is $3 or $1200 Jan 20 '18 at 5:14

I don't know what happened with your trade since there's a lot of conjecture involved (accurate data, time of execution, etc.) but let me suggest one possibility. High frequency traders do a lot of spoofing, particularly with illiquid stocks - and most stocks are illiquid in after hours trading. So placing a market order at what appears to be a good price ends up with a buy fill at a higher price.

As an example, a few days ago, with the price at $24.02 x $24.05, I tried buying XYZ shares at $24.05 at 4:02 PM (limit order). As fast as I clicked my buy order, the ask price jumped to $24.23 and I got nothing. As soon as I cancelled my order, the ask price dropped back to $24.05. I repeated this two more times with the same result. Had I placed a market order when XYZ was $24.05, I would have been filled at $24.23 and my broker would have told me the same thing that your did "That was the market at the time of your order."

The short answer? Do not place market orders unless it's a liquid stock with a narrow bid/ask during market hours.

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