One-hundred-forty characters can do a whole lotta damage. A Hillary Clinton tweet Sept. 21, deploring “outrageous” “price gouging” in the specialty drug market, saw the largest biotech ETF tank 5% on Sept. 21 on fears of pricing controls. At the end of the third quarter, iShares Nasdaq Biotechnology (IBB) had given up all its gains year to date on the back of roughly 11% losses in both September and August (it’s since rallied a tad).