Specialised Banking & Financial Regulatory Law Practice
Law firm founded by & for market professionals
Grégory das Mercês
Avocat – Barreau des Hauts de Seine
Combining legal & regulatory excellence
with front-line financial markets expertise
Greg’s career has been built at the crossroads of financial regulation, operations and investment management. This background gives him a rare, 360-degree understanding of how rules, risks and business realities interact.
At Euronext, he helped design key regulatory frameworks, combining technical insight into trading mechanisms with policy expertise. He eventually headed the Exchange’s Market Surveillance department, gaining first-hand exposure to market integrity and supervision in practice. He later joined Natixis, first as Compliance Officer, then as Head of Compliance for Equity Markets. There, he worked closely with trading and structuring teams to align innovation with regulatory expectations. His understanding of business drivers also led him to collaborate directly with front-office teams, contributing to the design, promotion and delivery of transactional services.This path ultimately led him to create and manage his own hedge fund and AIFM, gaining direct experience in investment management, risk oversight, capital formation and distribution.
Over time, he has built deep, front-line expertise across the full lifecycle of regulated activities — from policy drafting and complex entity structuring to enforcement actions (AMF/ACPR/CSSF), litigation and remediation. Known for his ability to translate complex regulatory and technical concepts into practical, operationally sound solutions, he brings a pragmatic understanding of how financial systems truly function.
In recent years, his personal investment and advisory work have broadened his focus toward the technological dimension of modern economies. He explores how data, automation, blockchain and AI reshape not only finance, but the way organisations operate and innovate.
Technical Expertise
- Trading Platforms & Market Infrastructures
- Prudential and Conduct Regulation
- Investment Product Structuring & Distribution
- Financial Technology and Data Governance
- Securities Financing & Derivatives
Our approach: Strategy, Market Insight & Precision
Our expertise spans the core areas where finance and technology converge, combining legal excellence with an acute understanding of markets, innovation, and regulation.
Regulatory
Financial Regulatory Strategy & Compliance
Explaining Before Complying
Because Explaining becomes increasingly more important than Complying, our practice focusses on delivering a unique blend of technical, legal and regulatory expertise in the field of financial markets and investment activities.
Securities & Derivatives
Securities Markets and Investment Structuring
Mastering Complexity in Financial Markets
Advising on Securities & Derivatives requires mastering their entire lifecycle — from issuance and pricing to trading, clearing, settlement and corporate actions. Erya bridges legal insight with deep operational expertise for market professionals.
Tech & AI
Fintech & AI Regulatory Governance
Shaping Tomorrow’s Technologies, Securing Today’s Compliance
In a world shaped by algorithms and data, Erya advises its clients on the regulatory challenges arising from emerging financial technology, offering strategic insight at the intersection of finance, AI, and digital services.
Our Practice
Erya services investors, financial institutions, and innovators by securing, structuring, and defending their operations. The firm’s services span the entire investment and regulatory cycle, offering strategic support from market entry to dispute resolution. With a focus on precision and foresight, Erya helps clients succeed in a rapidly evolving financial landscape.
- Banks & Credit institutions
- Asset Managers & Hedge Funds
- Platforms & Brokers
- Insurance companies & distributors
- Fintechs
- Regulatory Strategy & Compliance
- Regulatory Transactions
- Investment Structuring & Marketing
- Disputes and Contentious Regulation
Regulatory Strategy & Compliance
Erya advises banks, asset managers and insurers on all aspects of regulatory compliance, governance and conduct. Drawing on policy and operational experience, the firm designs, audits and strengthens compliance frameworks consistent with all financial and insurance sector regulations.
Services:
- Structuring conduct and prudential compliance frameworks.
- Assessing regulatory and legal risks (including tax implications related to trading and investment services).
- Strategic support during inspections and investigations (regulators, exchanges or audit functions).
Regulatory Transactions
Erya assists financial institutions, fintechs and market operators in structuring, obtaining and maintaining regulatory authorisations. The firm provides end-to-end support for permissioning, reorganisations and cross-border projects, ensuring that prudential and capital requirements are properly anticipated and authorisations are efficiently delivered.
Services:
- Advising clients during design and project phases to secure regulatory compliance and alignment with strategic objectives.
- Optimising capital and liquidity requirements.
- Interfacing with regulators in authorisation procedures for banks, investment firms, asset managers and fintechs.
Investment Structuring & Marketing
We advise on the design, approval and distribution of investment products and strategies, aligning legal structure with regulatory and financial constraints. Its practice covers the full product lifecycle — from structuring and documentation to marketing and post-trade oversight.
Services:
- Structuring and documentation (prospectuses, investment vehicles and contracts — GMRA / GMSLA / ISDA).
- Designing marketing policies and securing distribution networks for funds, structured products and alternative assets.
- Assisting in compliance with investor protection regulations (disclosure, value for money, suitability).
Disputes & Contentious Regulation
Erya represents and assists clients in financial and regulatory disputes, investigations and enforcement proceedings. Combining legal precision with market expertise, the firm supports in-house lawyers and external counsel in defining defence strategies and managing interactions with regulators.
Services:
- AMF / ACPR enforcement and disciplinary proceedings.
- Market and transaction disputes (valuation, failed settlements, counterparty defaults).
- Litigation involving derivatives, structured products, market abuse and SFTs.