5,185,414,108 ADA was distributed among 3 companies: IOHK, CF, and Emurgo. Later IOHK released a post, disclosing their address, that’s why it’s named in the explorer. Binance is also named only because they have disclosed it voluntarily, afaik. CF and Emurgo never did, idk why. Maybe they’ve distributed their shares so there are too many addresses, or whatnot. IOHK only had some slight movement on their address somewhere in December 2017 because they needed to give some ADA away as vested bonuses to partners or contractors, not sure. IOHK actually have the right to spend 33% from the moment of launch, another 33% since June 1 2018, and last 34% since June 1 2019, but they only have spent ~2% so far.