Apart from reaching a new ATH, bitcoin is also regaining dominance vs other alts. It was halved between March and June and bitcoin has been slowly regaining it but lately seems to have received a boost.

Source: (
https://coinmarketcap.com/charts/#dominance-percentage)
Any ideas about why this is happening?
Thats a normal economics, I dont think you need anyone to be giving you explanations all the time when such a thing happen. Even this December the price has been going up again, it goes up and it falls a bit then goes back up again. This week and last week has been the same, falling and picking up, although its more of going up than a falling. Hope the bulls gets in so that this will rise up once and for all.