MaxLinear (MXL) had the highest return on May 19 by a mid-cap US stock, returning 11.9%.

ASSET	DATE	% RETURN
MaxLinear (MXL)	5/19/2026	11.89%
RXO (RXO)	5/19/2026	11.62%
CleanSpark (CLSK)	5/19/2026	10.53%
Maase (MAAS)	5/19/2026	10.11%
Himax Technologies (HIMX)	5/19/2026	9.79%
Bilibili (BILI)	5/19/2026	8.81%
AXT (AXTI)	5/19/2026	8.54%
Century Aluminum (CENX)	5/19/2026	8.22%
Silicon Motion Technology (SIMO)	5/19/2026	7.94%
Butterfly Network (BFLY)	5/19/2026	7.61%
Synaptics (SYNA)	5/19/2026	7.45%
IPG Photonics (IPGP)	5/19/2026	7.08%
Liberty Global PLC Class B (LBTYB)	5/19/2026	7.07%
Tenable (TENB)	5/19/2026	6.63%
Option Care Health (OPCH)	5/19/2026	6.32%
Sellas Life Sciences (SLS)	5/19/2026	5.86%
Heartflow, Inc Common Stock (HTFL)	5/19/2026	5.35%
Liquidia Technologies (LQDA)	5/19/2026	5.28%
Hyperliquid Strategies Inc Common Stock (PURR)	5/19/2026	5.13%
Power Integrations (POWI)	5/19/2026	4.85%
Five9 (FIVN)	5/19/2026	4.7%
Seaboard (SEB)	5/19/2026	4.47%
Mobileye Global Inc Class A Common Stock (MBLY)	5/19/2026	4.32%
Acm Research (ACMR)	5/19/2026	4.32%
Avis Budget (CAR)	5/19/2026	4.2%

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