> One of the world’s most widely traded virtual currencies faces renewed doubts about its stability [...]
Tether is nothing in terms of crypto currency penetration. It does not even have a percent of daily trading. Then a few paragraphs down:
> [...] within an hour of the attorney general’s statement and Tether slid 1.4 percent.
1.4 per cent. Even big cap stocks fluctuate that much some days.
> At the time of the correspondence, Bitcoin was trading at around $6,500. It dropped 4.7 percent to $5,236.03 at 12:10 p.m. in Hong Kong on Friday.
So they mention a price from 8 months ago, and then mention yesterday's price, implying that it fell that much because of this event.
It's volume is 2nd only to Bitcoin per coinmarketcap.
With your 3rd point about pricing changes, yeah correlation/causation, it's a theory that is plausible though.
Same as why lending rates for crypto & fiat can go from 0.0001% to 0.08% (per day for example) in a matter of hours based on certain sudden price action.
Looking at coinmarket cap just now it's No 2 by 24hr trading volume. Bitcoin $18bn, Tether $16.5bn, Ethereum $8bn, all others less than 4.
If those were the prices before and after, the drop was 19.45%.