## daily-yearly liquidity
## https://en.wikipedia.org/wiki/Exchange-traded_fund
As of August 2021, $9 trillion was invested in ETFs globally, including $6.6 trillion invested in the U.S
[DB AM - review](https://etf.dws.com/en-gb/AssetDownload/Index/e2ff8ba8-6369-4c2b-8b6a-df5ed63b3226/Understanding-ETFs-A-ten-step-guide-to-Exchange-Traded-Funds.pdf/)
https://www.investopedia.com/articles/investing/032615/how-etf-arbitrage-works.asp
- https://www.bqprime.com/amp/business/etf-risks-are-misunderstood-by-regulators