Head of Portfolio Construction & implementation

Location: London

Reporting Line: Chief Investment Officer

Level for Referral Policy: Senior

Who We Are

Founded in 2002 as a pioneering hedge fund, Marble Bar has built its reputation on intellectual discipline, research, data-driven insight and a deep understanding of investment behaviours. Since its founding, the firm has helped portfolio managers identify repeatable processes within their investment practice and sustain their edge in constantly evolving markets. For over twenty years, we have successfully identified exceptional managers and created environments to help them generate durable returns.

Your Role

A rare opportunity to become a key architect of an institutional-quality investment business at launch. The CIO generates proprietary signals and owns the investment decisions; the fund trades within pre-committed tramlines - codified rules for sizing, hedging, refresh and risk. Your role is to run that machine brilliantly and make it better: ensuring the alpha generated is fully converted into portfolio returns through superior implementation, and being accountable at all times for how the book is positioned and why.

What You Will Own

• Day-to-day implementation of the portfolio: translating validated signals into live basket positions within the fund's construction framework.
• Hedging: implementation of portfolio- and security-level hedges - sector baskets, factor overlays, options - within the fund's hedging framework.
• Factor and risk monitoring: continuous ownership of factor tilts, exposures, and idiosyncratic vs factor risk decomposition.
• Execution quality: transaction cost analysis, liquidity management, and execution efficiency across the programme.
• The daily answer: complete, instant command of 'how are we doing today, and why?' - P&L attribution, hedge performance, positioning - for the CIO and, over time, for investors.
• Framework improvement via evidence: proposal rights (not change rights) on construction and hedging parameters, routed through a dedicated backtesting team and approved at committee.

How the Seat Works

Decision rights are explicit. The CIO owns signal content and investment decisions; parameters change only with evidence, via the backtest team and committee. Your discretion is deliberately limited at the outset and expands as trust builds - execution judgement first, then hedge implementation choices, then framework proposals. Implementation behaviour across the fund is measured through a proprietary behavioural analytics platform; the right candidate will find that feedback loop energising, not threatening.

What we are looking for

• Circa 8-15 years in sophisticated equity long/short environments: multi-manager platforms, systematic funds, central risk books, or institutional asset managers.
• Deep practical expertise in portfolio construction, baskets, hedging and factor management.
• Options experience is essential.
• Strong grasp of market microstructure, execution and transaction cost analysis.
• Python fluency helpful, not essential - the infrastructure team builds the tools; you must be able to interrogate them.

Who You Are

An investor first. Market-savvy and commercially minded, not a numbers-first quant. Hungry, entrepreneurial and hard-working. Analytically disciplined but led by market judgement. Constructive and comfortable challenging ideas, and equally comfortable operating within a disciplined, rules-based framework, because you believe that is how alpha survives into returns. A strong communicator with the potential to be client-facing as the platform grows.

This position requires you to be based in our London office from Monday to Friday. The working day begins at 07:30h London time, ahead of the European open.