ClearOne (CLRO) had the lowest return in March 1991 by a US stock, returning -94.1%.

ASSET	MONTH	% RETURN
ClearOne (CLRO)	March 1991	-94.07%
Insteel Industries (IIIN)	March 1991	-55.1%
Royal Gold (RGLD)	March 1991	-50.01%
Sanara Medtech (SMTI)	March 1991	-28.57%
Americas Car-Mart (CRMT)	March 1991	-25%
Pure Cycle (PCYO)	March 1991	-25%
McEwen Mining (MUX)	March 1991	-25%
American Vanguard (AVD)	March 1991	-22.93%
Tidewater (TDW)	March 1991	-22.38%
Vista Gold (VGZ)	March 1991	-21.74%
Lakeland Industries (LAKE)	March 1991	-21.05%
Ark Restaurants (ARKR)	March 1991	-20%
Richardson Electronics (RELL)	March 1991	-20%
Spectrum Brands (SPB)	March 1991	-20%
AAON (AAON)	March 1991	-19.13%
Hallador Energy (HNRG)	March 1991	-18.75%
Terex (TEX)	March 1991	-18.38%
Mount Logan Capital Inc Common Stock (MLCI)	March 1991	-18.18%
LSI Industries (LYTS)	March 1991	-18.17%
Citizens (CIA)	March 1991	-17.24%
Middleby (MIDD)	March 1991	-16.65%
CACI International (CACI)	March 1991	-15.87%
AMREP (AXR)	March 1991	-15.79%
Tutor Perini (TPC)	March 1991	-15.45%
Valmont Industries (VMI)	March 1991	-15.09%