Do genesis block owners still hold +50% of the total market cap?
The original 73 accounts from the genesis block transactions have a total balance of 286009248 nxt.
I thought there were 1,000,000,000 NXT in total. Are you saying there are only 286,009,248 NXT in existance?
No, I'm saying that if you sum the current balance of the 73 recipient accounts from the
genesis block transactions, you'll (now) get 280060111 nxt
remaining in the original 73 accounts.
You can look at the transactions on the those accounts and make some guesses that could possibly answer your question.