Avient (AVNT) had the lowest return between 1990 and 2000 by a US stock, returning -100%.

ASSET	YEARS	% RETURN
Avient (AVNT)	1990-2000	-100%
First National (FXNC)	1990-2000	-100%
Valley National Bancorp (VLY)	1990-2000	-100%
Reinsurance Group of America (RGA)	1990-2000	-100%
Natural Health Trend (NHTC)	1990-2000	-99.99%
Gulf Resources (GURE)	1990-2000	-99.75%
Coda Octopus (CODA)	1990-2000	-99.67%
Westwater Resources (WWR)	1990-2000	-99.23%
China Natural Resources (CHNR)	1990-2000	-99.17%
Palatin Technologies (PTN)	1990-2000	-99.11%
McEwen Mining (MUX)	1990-2000	-98.89%
Stonex (SNEX)	1990-2000	-98.7%
Issuer Direct (ISDR)	1990-2000	-98.67%
Arrowhead Pharmaceuticals (ARWR)	1990-2000	-98.61%
Odyssey Marine Exploration (OMEX)	1990-2000	-98.5%
Evolution Petroleum (EPM)	1990-2000	-98.49%
Booking (BKNG)	1990-2000	-98.38%
Caledonia Mining (CMCL)	1990-2000	-98.28%
Vista Gold (VGZ)	1990-2000	-97.97%
New Concept Energy (GBR)	1990-2000	-97.93%
Acadia Healthcare (ACHC)	1990-2000	-97.82%
Eagle Bancorp (EGBN)	1990-2000	-97.66%
Crown Crafts (CRWS)	1990-2000	-97.66%
MEDIFAST (MED)	1990-2000	-97.55%
Ammo (POWW)	1990-2000	-97.32%