Chopper Trading, LLC | 1,835 followers on LinkedIn. Chopper Trading LLC is a privately owned proprietary trading firm headquartered in Chicago’s historic Board of Trade Building with growing offices in New York, London, San Francisco and Washington DC. Our 200+ employees form a strategic blend of Traders, Software Engineers, and Quantitative Analysts that has consistently produced results since our founding in 2002. One key to this success has been the pledge to hire extremely bright, motivated, and passionate employees who are tasked with developing our proprietary trading applications and implementing these applications in the financial markets.