So I got invited to my second ex raid. The first one I did had 9 people. Which is weird because the the raid I did at that gym to get the pass there was so many people there we split into two groups. So anyway, my second ex raid so far has 32 people that have been confirmed invited. There is probably a few more as the passes went out yesterday afternoon. What is the most people anyone has seen invited to an ex raid? Seems like there is no rhyme or reason to how many people get invited.
It is a 60% chance of receiving the Ex Raid for the qualifying gym that you raided at. There are more factors that influence the chance such as Silver vs Gold status of that said gym. For every Ex raid you receive your chance of getting another one decreases 50% each time.
Source: https://thesilphroad.com/news/ex-raid-selection-criteria-data-says-december-1st-wave/
