Weatherford International (WFRD) had the best month in 2019 by a US stock with a market cap of $1B+ in May 2019, returning 11,631.1%.

ASSET	MONTH	% RETURN
Weatherford International (WFRD)	May 2019	11,631.11%
Fubotv (FUBO)	February 2019	2,367.25%
Mirum Pharmaceuticals (MIRM)	December 2019	235.43%
Axsome Therapeutics (AXSM)	January 2019	198.58%
BitMine Immersion Technologies (BMNR)	July 2019	175%
Fubotv (FUBO)	January 2019	158.47%
Axsome Therapeutics (AXSM)	December 2019	156.41%
Celldex Therapeutics (CLDX)	January 2019	153.9%
Aurinia Pharmaceuticals (AUPH)	December 2019	150.74%
Jumia Technologies (JMIA)	April 2019	126.75%
Immunitybio (IBRX)	December 2019	115.34%
Bloom Energy (BE)	November 2019	114.47%
CleanSpark (CLSK)	February 2019	113.95%
Revolve Group LLC (RVLV)	June 2019	91.67%
BW LPG (BWLP)	December 2019	87.47%
MiMedx (MDXG)	May 2019	87.24%
Insmed (INSM)	January 2019	86.57%
QXO (QXO)	February 2019	81.78%
Arrowhead Pharmaceuticals (ARWR)	November 2019	81.21%
Soleno Therapeutics (SLNO)	December 2019	80.37%
Axsome Therapeutics (AXSM)	March 2019	78.54%
Quantum Computing (QUBT)	January 2019	78.33%
Collegium Pharmaceutical (COLL)	November 2019	76.24%
Riot Blockchain (RIOT)	February 2019	74.86%
Amber International (AMBR)	January 2019	74.47%