I just noticed Coinbase going "unavailable" just at the moment of the largest dip, and then only becoming available again as it recovered somewhat. That does't seem a coincidence. They close it temporarily during large dips ... Kraken was also partially unresponsive during the dip.
This Coinbase company seems to be a large trader with big wallets. So seems to me their customers are trading against their wallets. i.e It is not like they connect buyers and sellers, but rather sell/buy to their customers from their own wallets.
Is Kraken and the other big ones the same ?
Same with our local exchange wallet here. They are trading with their customers. The downside too much margin between buy and sell rate since according to them, only few do selling while buying is highly demand. In terms of Coinbase, we can't really determined the exact thing why during the big rally they are always on maintenance.
Just make this as a reference:
"Coinbase is experiencing unprecedented traffic and trading volume and as a result has encountered outages and degraded performance.
As we experience rapid growth, we are also experiencing a high volume of support requests. We regret not being able to answer your inquiry in a reasonable amount of time."