Citadel Securities and HRT Financial have sharply increased their capital buffers over the past five years while Jane Street has pulled back, according to an analysis of regulatory filings that points to a significant reshaping of the US market-making landscape.
Net capital data drawn from annual X-17A-5 filings with the Securities and Exchange Commission show Citadel Securities grew its net capital fivefold since 2019, reaching $3.42bn by 2024. HRT Financial recorded an even steeper rise, expanding its capital base nearly tenfold from $265m to $2.53bn over the same period.
Jane Street has moved in the opposite direction. After building its net capital from $775m in 2019 to a peak of $1.88bn in 2021, the firm reduced its buffer to $1.22bn by 2024, a decline of 35 per cent from its high point. HRT’s capital base now exceeds Jane Street’s, a reversal that would have appeared unlikely five years ago.
The diverging trajectories reflect differing strategic responses to a volatile period in financial markets. The Covid-19 pandemic created exceptional trading opportunities for firms able to provide liquidity under stress conditions. All three expanded rapidly in 2020, with Jane Street more than doubling its net capital and HRT more than tripling its cushion that year.
Since then, however, the paths have separated. Citadel Securities, which handles roughly a quarter of all US equity trading volume, has continued to build capital at approximately $700m per year since 2021, a pace that suggests both sustained profitability and a deliberate decision to retain earnings within its broker-dealer entity.
Jane Street’s retreat warrants scrutiny. The firm held net capital steady at around $1.84bn through 2022 and 2023 before reducing it by $620m in 2024. The reduction could reflect distributions to partners, capital allocation to non-US entities, or a strategic preference for a leaner balance sheet. Jane Street’s broader business remains highly profitable — the firm reportedly generated $10bn in net trading revenue in 2024 — suggesting the lower capital level is a matter of choice rather than constraint.
Among smaller participants, the filings reveal a pronounced disparity in scale. Susquehanna Securities, XTX Markets and Jump Trading maintain net capital measured in millions rather than billions, though this may partly reflect corporate structures in which principal trading occurs through affiliated entities not captured in SEC filings. Jump Trading’s figures show particular volatility, with net capital fluctuating between $68,000 and $221,000, suggesting its registered entity functions largely as a market access vehicle.
The concentration of capital among a smaller number of dominant firms has broader implications for market structure. Regulators, including the SEC through its proposed equity market reforms, have increased scrutiny of market power in trading. Greater capital concentration may support liquidity provision under normal conditions while potentially amplifying systemic risk during periods of dislocation.
On current evidence from the filings, Citadel Securities and HRT are widening their lead over rivals in the market-making hierarchy.