I'm curious about some publications mentioning that "only 2% of the addresses holds 1 Bitcoin or more".
I found this to be quite surprising, since I always supposed longtime hodlers to be the larger segment of the Bitcoin ecosystem and not just a small fraction.
How accurate this data could be?
I don't think all the data is avaliable for the general public. So there should definitely be some form of guessing and estimating be involved in determining who holds the most bitcoins. There might be some fund who show their bitcoin holdings but this is only a part of the overall market. Also there could be some rich families who are very keen on holding bitcoins but don't share their holdings publicly.