  Stable coins are not very stable. Cash collateralized coins are more stable,
but the overall failure rate is similar to tokens that are not designed to be
stable. USD Coin, Tether and Dai have the largest Ethereum market shares, and
they have an average velocity nearly three times higher than M1. Centralized
and decentralized exchanges are the most active nodes and largest holders on
the blockchain. Four of the top ten tokens have Herfindahl indices higher than
the U.S. banking system. Median gas fees for Tether rose more than twelve times
over the last two years, and nearly twenty times for USD Coin. Transactions of
under 50,000 USD can generally be done more cheaply offchain. 24 hour exchange
turnover in Tether is nearly 60 billion USD. This is comparable to the daily
volume at the NYSE and eight times the daily flow in money market mutual funds.
Narrow bid-ask spreads and depth have attracted HFT participation approaching
50%
