I generated this Excel chart to provide an idea as to what the number will be to determine how many shares of XOM we will get for our $45 per IOC share. It looks encouraging for IOC shareholders.
The buyout agreement talks of the volume weighted average price for 10 consecutive days running up to and including the 2nd day before the closing date. Some think the closing date will be Sept 27. If so, then the calculation for this number should run from Sept 12 to Sept 23 (10 trading days).
I've plotted two volume weighted average price curves below. The green curve is a rolling 10 day volume weighted average price. So this simply shows how the 10 day average is trending.
The blue curve is another volume weighted average price curve but cumulates the data beginning with data starting on Sept 12. So if in fact this deal closes on Sept 27, then the value in this curve on the close of Sept 23 will be the XOM pps value they actually use (if calculated using closing prices). And that value will match the Green curve on that date.
The good thing is XOM pps has been trending lower and the volume has been trending higher. The curves continued to trend downward, even though XOM closed up 1% today. That's the benefit of volume weighted multiday averages.
All we need is a large black swan day to knock XOM down 20% and volume up 100+% to really improve our deal.
The bad news for XOM recently with the SEC and now with analysts downgrading the outlook, which seems to be snowballing negatively, is to our advantage if it continues. XOM was up only 0.92% today while CVX was up 1.98%, TOT up 2.01% and RDS-A up 2.00%.

