AI / ML Engineer Salary in Illinois (2026)

Worth knowing: Citadel + Citadel Securities is the structural depth feature most national AI/ML-career surveys understate for IL. Citadel (multi-strategy hedge fund, ~$70B AUM, ~2K Chicago employees + global) + Citadel Securities (market-maker handling ~25% of US equities volume, ~1.5K Chicago employees + global) together operate one of the country's most sophisticated quantitative ML research organizations — sub-millisecond latency execution, market-making models, derivatives pricing models, and signals research drive top-tier quant compensation. Senior Citadel quant researchers + ML engineers routinely clear $385K-$1.25M+ TC with substantial carry-component bonus structures. The broader Chicago HFT cluster (DRW Trading, Jump Trading, Optiver, IMC, Akuna Capital, Wolverine Trading, TradeBot) creates one of the country's largest concentrations of senior quant ML talent. Tempus AI Chicago (founded 2015, ~3K employees, the largest healthcare AI company by employee count post-2024 IPO) operates substantial clinical-data + genomics + cancer-specific ML. Argonne National Laboratory (DOE-funded, ~3.5K employees, operates the Aurora supercomputer — one of the country's most powerful systems) drives scientific ML research. IL's 4.95% flat tax plus NO Chicago city earnings tax (distinctive vs NYC/SF/Philadelphia) creates substantially favorable senior quant tax structure — a $500K Citadel quant pays $24.75K IL state tax vs $40K+ in NY at equivalent comp.