AMF France v. Sylvain Duport (layering, 2019)

Settled

✓ Checked against the primary document on October 5, 2026. The library's summary, tags and figures for this record were compared with the regulator's own document by an AI model (Claude) following written instructions, in a single reading of the French decision; an independent second reading of 60 of the AMF records agreed on every field for 54 and on the core fields for 59. No lawyer has reviewed them. A checked record can still contain errors, and checked does not mean endorsed. See how we check records or report a correction.

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In February 2019 the AMF agreed a settlement with the trader Sylvain Duport over 14 sequences in nine shares in which he allegedly bought aggressively, posted passive bids he then cancelled, and sold into the move; he agreed to pay EUR 240,000.

The record

What was ordered

Civil penalty

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Disgorgement

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Prejudgment interest

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Total relief

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Alleged gain

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Penalty as published

€240k

A dash means the release did not state a figure we could extract, not that the figure is zero. Penalty and disgorgement are stored separately so aggregates across the library do not double-count the same dollars. This regulator states penalties in EUR. The figure is recorded as published and is not converted, so it does not appear in the USD totals or medians used elsewhere on this site.

What is alleged to have happened

The AMF published an administrative settlement (accord de composition administrative) with Sylvain Duport, dated 11 February 2019. This is not a contested sanctions hearing. The agreement took effect only once the AMF Collège validated it and the Commission des sanctions homologated it; the document gives the signing date but not the homologation date, so the signing date is used here.

The AMF opened an investigation in November 2016 into nine shares on compartments B and C of Euronext Paris. It identified 14 sequences between 3 March 2014 and 8 December 2016 in which Mr Duport’s trading could have set prices at an artificial level or given false signals.

The first grievance was that he built a position aggressively, was the largest buyer in each sequence and more than half of volume in ten, saw prices rise at least 3% and then fall back within two hours, with price reservations in nine sequences. The second was that he entered large passive bids that were cancelled before execution while he was selling, at least half of his passive bids going unexecuted. The sequences produced a total profit of EUR 81,008.

He denied any intent to manipulate and noted the agreement is not an admission of guilt. He agreed to pay EUR 240,000 to the Treasury. The agreement records that the Parquet national financier told the AMF on 18 September 2018 that it did not wish to bring a prosecution against him for these facts, so no criminal case is stated.

What the record does not show: the agreement describes conduct that the person "could" or "would" have committed, so it records allegations and undertakings, not a finding of breach, and it is not styled as a fine. It does not show whether any later challenge occurred.

This library tags the matter as layering, price manipulation. The tagging is ours, not the regulator's.

For the regulator's own account of the facts, read the primary document linked above. This page deliberately summarises the structured record rather than reproducing the decision.

What technique is this, and how does it work?

This action is tagged with 2 techniques in our taxonomy. The tagging is ours: regulators charge statutory provisions, not technique names, so the mapping is an editorial judgement described in our editorial policy.

• Layering — see how it works, what statute it engages, and every other action tagged the same way.
• Price manipulation — see how it works, what statute it engages, and every other action tagged the same way.

Timeline

1. 2019-02-11 Settlement agreed (homologated by the Commission des sanctions)

Primary documents

Everything on this page derives from the documents below. Where our summary and the primary document disagree, the primary document is right.

• AMF settlement page
• Settlement (PDF, French)

The linked release is published by the issuing regulator under its own terms. Our summary and narrative above are our own writing.

Related actions

Other actions in the library sharing at least one technique tag with this one.

Record added October 5, 2026. submit a correction.