Southwest Airlines (LUV) had the lowest return between 1975 and 1986 by a large-cap US stock, returning -99.6%.

ASSET	YEARS	% RETURN
Southwest Airlines (LUV)	1975-1986	-99.63%
Semtech (SMTC)	1975-1986	-83.62%
Ross Stores (ROST)	1975-1986	-73.41%
Valero Energy (VLO)	1975-1986	-69.49%
Micron Technology (MU)	1975-1986	-68.14%
Lam Research (LRCX)	1975-1986	-55.02%
Jack Henry & Associates (JKHY)	1975-1986	-53.73%
Devon Energy (DVN)	1975-1986	-53.57%
MasTec (MTZ)	1975-1986	-48.72%
Monster Beverage (MNST)	1975-1986	-39.94%
Onto Innovation (ONTO)	1975-1986	-39.2%
Hecla Mining (HL)	1975-1986	-34.68%
Schlumberger (SLB)	1975-1986	-34.58%
Arrow Electronics (ARW)	1975-1986	-33.17%
Universal Health Services (UHS)	1975-1986	-30.86%
Teva Pharma Industries Ltd ADR (TEVA)	1975-1986	-28.53%
Stifel Financial (SF)	1975-1986	-26.85%
Texas Pacific Land (TPL)	1975-1986	-25.12%
KLA (KLAC)	1975-1986	-24.3%
Intel (INTC)	1975-1986	-23.63%
Repligen (RGEN)	1975-1986	-22.65%
Gold Fields Ltd ADR (GFI)	1975-1986	-21.48%
AngloGold Ashanti (AU)	1975-1986	-20.81%
L3Harris Technologies (LHX)	1975-1986	-15.63%
First Citizens BancShares (FCNCA)	1975-1986	-15.54%

Large-cap stocks are treated as having a market cap of $10B+.