The owner of the Bitcoinica site has released some data from his site which may reflect the wider bitcoin economy. He gives a value for the Gini coefficient of:
Gini Coefficient = 0.87709
The Bitcoin Report site also releases a regular report on the number of bitcoins in the top 100 wallets. Although one person can own multiple wallets or a wallet of a exchange (e.g. MtGox) may contain coins with multiple owners so it is impossible to know for certain the real wealth distribution but it may have some correlation.
The Bitcoin Trader blog used the Bitcoin report data on the top 100 wallets and compared the data from May 1st and Oct. 29th 2011.
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From the Bitcoin Trader:
The distribution of coins among the top 100 has evened out, as can be seen in the chart.
Even though 1,310,000 Bitcoins have been mined since May 1st, the top 100 have still managed to increase their relative wealth, and now hold 29.8% of all the Bitcoins ever created!
While certainly not perfect these type of statistics may be give some indication of the trends in the wealth distribution in the bitcoin economy.
@dave-perry perhaps you could explain why. your comment is pretty flat without further explanation, which im sure the community would be happy to hear. – gesell – 2013-02-18T20:42:41.470
1There is no real way to know. People might spread their holdings over several addresses, and one address can be a cold Mt. Gox store for a huge portion of the economy, and not owned by any single individual. – ripper234 – 2011-08-31T00:58:27.540
1In its current form this question is not terribly constructive, since it is poorly phrased and has no real way of being answered. I would encourage a rephrasing such as "Is it possible to estimate the Gini coefficient for Bitcoins?" The answer to this would be no, but it would be constructive and helpful if answered well. – eMansipater – 2011-08-31T01:00:44.930
1I re-phrased the question based on the feedback above. – kirian – 2011-08-31T01:29:17.347
2The fact that some folks don't see how to do it now is no reason to close the question. I suggest it be reopened. – nealmcb – 2011-08-31T04:01:45.530
2I also think that the question is perfectly valid, and I would be very curious to read a good no answer, since I would naively expect it to be possible to at least approximate. – Artem Kaznatcheev – 2011-09-02T00:54:49.387
3The Gini Coefficient doesn't seem like it would be very useful for such a small economy. Ask again when bitcoin has a significantly larger network and you might get a useful answer. – David Perry – 2011-08-30T22:35:38.140