There is a simple answer to the title question
Gascorp have diluted their asset by 33% to list
Listing will increase the p/e value by 2-3 times
Now do the math.
also,
they haven't sold - they have taken over the shell (Moby)
That is generally what happens when you own 60%
It is a simple backdoor float.
Gascorp is hitting the market when it is hot about Artemis.