I was reading about an Atlassian security vulnerability and was curious as to the effects on its stock price. Surprisingly, its stock price over the past 5 days was up 6.83%!? But I checked and Monday was a public holiday in the US and therefore the NASDAQ wasn't trading, hence the price is Friday's price, as indicated by the date on the chart (Sept 3rd):
So, purely out of curiosity, I wonder: other than reading expert opinion, is there any way to estimate, preferably through data and inference, what a stock price will be when a market isn't open? Or more precisely, what a stock price will be when the market does eventually open?
Note: I considered trying to infer what a stock is selling for privately (off market) in transactions close to the time of the market opening. But I'm not sure if such transactions occur frequently enough, nor whether the public can actually access the prices of these trades (since they occur off-market and possibly under confidential arrangements).