The article did not state that the wallet belongs to Nakamoto and it is still under investigation and they do not have a concrete evidence that Nakamoto indeed owns that wallet, we never know but maybe it is under one whale in the past who suddenly have a need to sell his shares it is still under investigation.
who has 500,000 or more Bitcoins ??
Might want to take a look at the bitcoin richlist instead. Wallets that holds the biggest amounts of bitcoin are the exchanges, which is to be expected: