As the markets on PredictIt become more liquid, it is of more significant concern that all participants are aware of the underlying order matching algorithm. Is it FIFO? Pro Rata / Allocation? Some combination of these? I don't necessarily have an opinion on which one is "right" but I think we at least need to know what method is being used so that we can discuss it.
The link below provides an outline of the most common order matching algorithms.
Good question! I don't know why this was never clarified.
We use FIFO.
FIFO stands for "first in, first out". It simply means that we will sell off your shares in the same order that you bought them. When you place an offer to sell shares, the platform will scan to see which shares were purchased first, regardless of the price they were purchased at, and sell them in the same order they were purchased. This is the method used on regulated U.S. exchanges. PredictIt has adopted the same method.
Can someone from PredictIt please chime in here? I'm still curious.
@ChillTomG do you work for PredictIt or is this just based on your observations? I tend to agree with you but I want PredictIt to officially address the specific distinctions referenced above.
From my experience, It is FIFO for bid to ask contract matching
Excellent Dave. Thanks for the clarification!