Devon Energy (DVN) had the highest return in February 1989 by a US stock in the S&P 500 (GSPC), returning 43.6%.

ASSET	MONTH	% RETURN
Devon Energy (DVN)	February 1989	43.59%
Fair Isaac (FICO)	February 1989	30.53%
UnitedHealth (UNH)	February 1989	27.45%
Ross Stores (ROST)	February 1989	20.46%
Skyworks Solutions (SWKS)	February 1989	20%
Newmont Goldcorp (NEM)	February 1989	16.24%
Monster Beverage (MNST)	February 1989	15.08%
MGM Resorts International (MGM)	February 1989	15%
Universal Health Services (UHS)	February 1989	13.33%
Home Depot (HD)	February 1989	12.11%
Bank of America (BAC)	February 1989	11.75%
Micron Technology (MU)	February 1989	10.63%
Progressive (PGR)	February 1989	10.24%
KLA-Tencor (KLAC)	February 1989	10.21%
Lockheed Martin (LMT)	February 1989	9.6%
Thermo Fisher Scientific (TMO)	February 1989	8.81%
Bank of New York Mellon (BK)	February 1989	8.66%
Expeditors International of Washington (EXPD)	February 1989	7.7%
Valero Energy (VLO)	February 1989	6.66%
ONEOK (OKE)	February 1989	6.55%
Teleflex (TFX)	February 1989	6.19%
Tyler Technologies (TYL)	February 1989	5.88%
Northrop Grumman (NOC)	February 1989	5.82%
Abbott Laboratories (ABT)	February 1989	5.69%
Raymond James Financial (RJF)	February 1989	5.15%