Axsome Therapeutics (AXSM) had the highest return in March 2019 by a mid-cap US stock, returning 78.5%.

ASSET	MONTH	% RETURN
Axsome Therapeutics (AXSM)	March 2019	78.54%
Protagonist Therapeutics (PTGX)	March 2019	56.54%
Skeena Resources (SKE)	March 2019	43.89%
Krystal Biotech (KRYS)	March 2019	43.11%
Acm Research (ACMR)	March 2019	34.17%
Plug Power (PLUG)	March 2019	33.33%
StoneCo (STNE)	March 2019	33.04%
OneSpaWorld (OSW)	March 2019	32.75%
ELF Beauty (ELF)	March 2019	32.5%
Definium Therapeutics (DFTX)	March 2019	31.11%
Almonty Industries Inc Common Shares (ALM)	March 2019	28.84%
Dianthus Therapeutics (DNTH)	March 2019	25.82%
Calumet Specialty Products Partners (CLMT)	March 2019	25.35%
Torm PLC Class A (TRMD)	March 2019	25.21%
YETI (YETI)	March 2019	24.9%
Veracyte (VCYT)	March 2019	23.25%
Iridium Communications (IRDM)	March 2019	22.35%
Abercrombie & Fitch (ANF)	March 2019	22.23%
TransAlta (TAC)	March 2019	21.32%
TG Therapeutics (TGTX)	March 2019	20.36%
Celsius (CELH)	March 2019	19.66%
Select Energy Services (WTTR)	March 2019	18.54%
Conagra Brands (CAG)	March 2019	18.45%
JOYY (JOYY)	March 2019	17.99%
Talos Energy (TALO)	March 2019	17.83%

Mid-cap stocks are treated as having a market cap between $2B and $10B.