Stock price when the opinion was issued
Now paying 15-20 bps higher than a plain-vanilla high-interest savings ETF. Good if you need access to cash, never drops below where you bought it if you buy on the ex-dividend date. A cash-like position in your portfolio. Pays interest.
The sawtooth graph is explained as money accumulating on short-term paper holdings, and then paid out all at once every month. You can, of course, automatically reinvest the proceeds.
The more in money market you are, the safer it is because the time to maturity of holding assets is lower. So the shorter the duration, the safer. The more government, the safer, but also a lower yield.
For an enhanced money market yield, he really likes ZST.