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Hartree Partners
Hartree Partners deploys proprietary capital across global commodities and energy infrastructure from trading hubs in New York, London, and San Mateo.
Hartree Partners
Hartree Partners was founded in 1997 by Stephen Semlitz and Guy Merison, originating from the over-the-counter energy derivatives group at Hess Energy Trading Company (HETCO). The firm launched as a boutique structured-products desk, specializing in complex gas and power derivatives during the deregulation of US energy markets. Over two decades, Hartree expanded from financial intermediation into physical commodity merchanting — owning and operating hard assets across the supply chain, including natural gas storage facilities, refined products terminals, and power generation assets in Europe and North America. The firm operates at the intersection of physical merchant trading and asset-backed investing. Its strategy spans natural gas, crude oil, refined products, power, metals, and agricultural commodities, with a heavy emphasis on European gas and global LNG since 2015. Hartree is not a pure asset manager — it deploys proprietary capital into physical infrastructure and working-capital-intensive trading books. The firm acquired a controlling stake in UK energy supplier British Gas Business in 2022, a deal that integrated trading, supply, and physical hedging operations under one roof (per the firm's official communications, 2022). Its metals desk is one of the largest non-bank participants in the London Metal Exchange base metals complex, and its agricultural trading group, Hartree Commodities, built a significant presence in Brazilian grain origination. The firm maintains trading hubs in New York, London, and San Mateo, with additional offices in Raleigh, Durham, and Hellerup, Denmark, mirroring its geographic allocation. Total headcount is not publicly disclosed. Hartree's capital base is opaque by design — the firm does not report assets under management, but industry estimates place its total committed and deployed capital in the single-digit billions. In December 2022, Hartree Partners formed a strategic partnership with EIG, a Washington, D.C.-based institutional energy investor, which acquired a minority stake in the firm — a transaction that signaled both external validation and a vehicle for scaling its energy transition investments (per Hartree Partners press release, December 2022). What distinguishes Hartree Partners is its hybrid architecture. The firm is a partnership, not a fund manager — trading principals co-invest their own capital alongside institutional coinvestors without a traditional fund-raise cycle. This aligns incentives around P&L performance rather than management fees, a structure rare outside of legacy merchant trading houses like Vitol or Trafigura. The EIG partnership introduced a permanent capital vehicle — Hartree Bulk Storage LLC — specifically for acquiring and operating midstream energy infrastructure, suggesting the firm is building an institutional-grade asset platform while preserving its principal-trading DNA.
General information
Firm type
Asset Manager
Year founded
1997
AUM
Undisclosed
Location
Region
North America
Country
United States
City
New York
Corporate office
New York, NY, United States
Additional offices
London, United Kingdom · San Mateo, CA, United States
Principals
Stephen Semlitz
Managing Director
Guy Merison
Managing Director
Sector focus
Frequently asked questions
How does Hartree Partners source its proprietary deal flow?
Hartree's origination model is anchored in physical merchant trading. The firm moves molecules and electrons — natural gas, crude, power, metals, grains — which generates proprietary market intelligence and bidirectional flow with producers, utilities, and industrials. This physical footprint gives Hartree visibility into supply-demand imbalances well before financial markets price them, a structural edge shared by the large merchant trading houses.
Is Hartree Partners a family office or a commodity trading house?
Hartree Partners is a privately held merchant partnership, not a family office. It deploys proprietary capital and co-investment alongside select institutional partners, but does not manage third-party capital in a traditional asset-management framework. Its business model — principal trading plus physical asset ownership — is structurally closer to Vitol or Mercuria than to a family office or private equity fund.
What is Hartree's relationship with EIG?
In December 2022, EIG, a Washington, D.C.-based institutional energy and infrastructure investor, acquired a minority equity stake in Hartree Partners. The partnership was structured to co-invest in energy infrastructure and energy transition opportunities, including midstream assets held through a dedicated vehicle called Hartree Bulk Storage LLC. The transaction did not change Hartree's operational autonomy as a merchant partnership.
Which commodities does Hartree Partners actively trade and invest in?
Hartree's portfolio spans natural gas, LNG, crude oil, refined products, power, base metals, and agricultural commodities. The firm's European gas and power desk is one of the largest non-utility participants in the market. Its metals group is an active London Metal Exchange member, and its agricultural trading arm, Hartree Commodities, has a material presence in South American grain origination.
Does Hartree Partners manage outside investor capital or operate funds?
Hartree does not operate as a traditional fund manager. The partnership structure means principals deploy their own capital alongside co-investors on a deal-by-deal basis or through permanent capital vehicles like Hartree Bulk Storage. There is no publicly reported flagship fund, no quarterly redemption structure, and no stated AUM — the model is P&L-driven merchant capital.
What is the regulatory structure for Hartree's European trading operations?
Hartree Partners' London entity is authorized and regulated by the UK Financial Conduct Authority. The firm's European power and gas trading operations are subject to REMIT and EMIR reporting requirements, and its position limits compliance is monitored as a non-bank commodity dealer in the UK and EU markets.
How is Hartree Partners governed?
Hartree operates as a private partnership with a flat governance structure centered on its managing directors and senior trading principals. There is no publicly listed board of directors, and leadership decisions are not disclosed externally. The EIG minority investment introduced an external institutional voice but did not alter the partnership's control, which remains with the founding and managing principals.
Profile maintained by Altss using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.
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