
Of the nearly 30,000 minutes in this timeframe, only 15 registered a median price swing of more than 1%. The largest median price swing was 3.6% on October 23 at 10:42 pm UTC.
The chart below zooms in on the higher volume instruments during the 10 most volatile minutes in this timeframe.

ntraminute price variations are largely clustered except for the four most volatile minutes. In the most volatile minute, Bitstamp and Bitfinex’s BTC-USD instruments swung the least, Binance’s BTC-BUSD the most, followed by LMAX’s BTC-USD. By far the highest volume instrument in this minute was Binance BTC-USDT at 1.5k BTC traded, followed by Coinbase at 1.1k BTC. In the next most volatile minute, OKX and Binance BTC-USDT are virtually tied at 1.9k BTC, followed again by Coinbase at 900 BTC.
These most volatile minutes have volume profiles that are distinct from the average minute. Surprisingly, the breakdown of volumes is actually fairly consistent when volatility is highest. The chart on the left shows volume share by exchange for the 10 most volatile minutes in the same time period as above. Coinbase regularly captures about 10%, LMAX 7%, Kraken 5%, Bitstamp 5%, Bybit 10%, and Binance about 35%.

In average minutes, Binance often captures more than 50% share (in large part driven by its no-fee BTC-FDUSD instrument), while MEXC, which also has no fees and whose share is too small to see on the left, captures between 5% and 15%. Kraken, LMAX, and Bitstamp all have significantly smaller shares on the right. Meanwhile, Coinbase varies between 1% and 15%.
Finally, we can compare this to the same time period in 2021 to see how things have changed since the SEC’s last batch of rejections.

Besides the most volatile two minutes on the left, Coinbase, Itbit, LMAX, Kraken, Gemini, and Bitstamp, the exchanges on which BlackRock’s ETF pricing would be based, accounted for around 30% of volumes. This is roughly the same as now, the main difference being that Binance has absorbed market share from FTX, HTX, and other off-shore exchanges, while much of Itbit and Gemini’s share has been taken by other U.S. exchanges. Coinbase’s market share was smaller and less consistent than it is today.
conclusion
So, is the surveillance sharing agreement with Coinbase enough? Since 2021, the exchange has grown its market share during the most volatile minutes and consistently has the 2nd or 3rd highest volumes when prices are swinging the most. Put simply, it’s hard to imagine a scenario in which an entity could manipulate an ETF’s price over a short time frame without also attempting to manipulate the price on Coinbase, meaning it should fit the definition of “significant market”. Should this not be enough, a self-regulatory organization like the Intermarket Surveillance Group – in this case composed of top crypto exchanges – would further bolster the anti-manipulation case and likely serve as a net positive to the industry in the long run.