CleanSpark (CLSK) had the highest return in May 2015 by a US stock, returning 1,088.1%.

ASSET	MONTH	% RETURN
CleanSpark (CLSK)	May 2015	1,088.11%
Immutep Ltd ADR (IMMP)	May 2015	307.16%
Abeona Therapeutics (ABEO)	May 2015	181.36%
Zivo Bioscience (ZIVO)	May 2015	143.53%
Sarepta Therapeutics (SRPT)	May 2015	108.8%
Enveric Biosciences (ENVB)	May 2015	98.77%
AmpliTech (AMPG)	May 2015	84.56%
Precipio (PRPO)	May 2015	82.64%
Heron Therapeuti (HRTX)	May 2015	82.62%
aTyr Pharma (ATYR)	May 2015	72.75%
Marker Therapeutics (MRKR)	May 2015	69.79%
Hello (MOMO)	May 2015	63.44%
Coda Octopus (CODA)	May 2015	61.54%
Sharplink Gaming (SBET)	May 2015	57.89%
Actinium Pharmaceuticals (ATNM)	May 2015	56.97%
Flexible Solutions International (FSI)	May 2015	55.18%
Natural Health Trend (NHTC)	May 2015	55.13%
Tucows (TCX)	May 2015	54.01%
Milestone Scientific (MLSS)	May 2015	53.85%
Blueprint Medicines (BPMC)	May 2015	52.69%
Ultragenyx (RARE)	May 2015	51.94%
Kalvista Pharmaceuticals (KALV)	May 2015	48.02%
Ryerson (RYI)	May 2015	47.43%
Travere Therapeutics (TVTX)	May 2015	46.28%
Pangaea Logistic (PANL)	May 2015	45.91%