YPF Sociedad Anonima (YPF) had the worst day in May 2020 by a large-cap US stock on May 13, 2020, returning -16.8%.

ASSET	DATE	% RETURN
YPF Sociedad Anonima (YPF)	5/13/2020	-16.78%
Hut 8 Corp Common Stock (HUT)	5/11/2020	-16.36%
Occidental Petroleum (OXY)	5/6/2020	-13.6%
Permian Resources (PR)	5/13/2020	-13.33%
Woodward (WWD)	5/5/2020	-13.2%
Moderna (MRNA)	5/26/2020	-13.06%
Permian Resources (PR)	5/6/2020	-12.41%
Permian Resources (PR)	5/1/2020	-12.14%
Hut 8 Corp Common Stock (HUT)	5/15/2020	-11.61%
Antero Resources (AR)	5/13/2020	-11.5%
Diamondback Energy (FANG)	5/5/2020	-11.44%
BioNTech SE (BNTX)	5/19/2020	-11.25%
Ovintiv (OVV)	5/5/2020	-11.13%
Wayfair (W)	5/18/2020	-11.08%
Hut 8 Corp Common Stock (HUT)	5/13/2020	-11.03%
Bloom Energy (BE)	5/13/2020	-10.69%
Royal Caribbean Cruises (RCL)	5/5/2020	-10.64%
SPX (SPXC)	5/1/2020	-10.6%
Summit Therapeutics (SMMT)	5/1/2020	-10.57%
Plains All American Pipeline (PAA)	5/5/2020	-10.43%
Western Midstream Partners (WES)	5/6/2020	-10.38%
Banco Bradesco S/A ADR (BBDO)	5/22/2020	-10.29%
Fabrinet (FN)	5/5/2020	-10.2%
Sitime (SITM)	5/19/2020	-10.17%
Antero Resources (AR)	5/6/2020	-9.97%

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