Cum-cum: warnings before the 2018 scandal

The cum-cum investigation, part 2

France’s tax authority was already challenging cum-cum transactions in 2017. A year later, the CumEx Files brought the issue to international public attention. Public records trace both the tax work and the revelations, then connect them in Crédit Agricole CIB’s judicial agreement. S03, IV.A.2 S04 S09, paragraphs 7–16

An earlier trace appears in a report by the European Securities and Markets Authority, ESMA. In 2009, France’s markets regulator, the AMF, shared surveillance findings concerning tax-related transactions with the tax authority. That account concerns tax planning broadly. Cum-cum reassessment proposals are specifically documented from 2017. S01, paragraph 117 S03, IV.A.2

Following the first article on the dividend mechanism, this investigation follows the warnings. Spotting a securities transfer, understanding its contracts and opening a tax challenge call on different information and powers. Connecting the records helps explain the institutional response; establishing individual responsibility requires evidence identifying the people involved.

Germany’s 1978 warning

The German precedent predates electronic trading. A Bundestag inquiry report published in June 2017 revisits a Finance Ministry letter of 2 August 1978. The letter described non-residents selling shares to residents before a distribution and buying them back afterwards. The benefit sought was a tax credit available to the resident buyer. Germany’s tax administration regarded arrangements without another economic purpose as an abuse of legal forms. S02, page 114

On 20 December 1978, the German banking association warned its members in turn. The parliamentary report describes a practical difficulty: a bank issuing a tax certificate might fail to recognise the problematic transaction behind the securities movements it processed. S02, page 115

That record illuminates an enduring feature of dividend arbitrage: a stream of income is temporarily placed with someone whose tax treatment makes it more valuable. The German arrangement at issue involved a tax credit. Modern French cases concern, among other things, the avoidance of withholding tax, the amount deducted when a dividend is paid to a non-resident. Each jurisdiction’s rules, instruments and legal characterisations need to be considered separately. S02, pages 114–115 S14, point 1

The 1978 precedent gives the mechanism a longer history. It cannot provide a starting date for calculating French losses. Its more immediate lesson concerns organisation: the same deal may look like a routine movement of securities to the person processing it and the temporary purchase of a tax advantage to the person designing it. Reconstructing the whole transaction becomes a prerequisite for effective scrutiny.

Cum-cum and cum-ex must also remain distinct throughout this history. Cum-cum can use a temporary change in share ownership to obtain different tax treatment. Cum-ex cases involving multiple reclaims concern credits or refunds without sufficient corresponding tax having been withheld. A shared media investigation can bring both to public attention while their evidence and legal treatment follow different paths. S01, section 3 S14, point 1

French tax challenges were under way in 2017

ESMA dates regular exchanges between the AMF and France’s tax authority to May 2017. The Senate report places the earliest cum-cum reassessment proposals it identifies in the same year. These were different activities: one involved technical cooperation; the other involved formally challenging a taxpayer’s treatment of particular transactions. S01, paragraph 118 S03, IV.A.2

Taken together, the dates are significant. A proposed reassessment shows that tax work has reached the stage of a formal claim. Reconstructing the entire process would also require the audit’s opening date, the transactions examined, the arguments exchanged and the outcome. The Senate provides an aggregate historical marker without publishing the individual documents needed to trace every case.

There is another distinction to preserve: when an event occurred and when the document describing it was issued. The 2009 transfer of information is recorded here in a 2020 report; the 2017 reassessments appear in a 2022 report. Those reference dates tell readers where the information can be checked. They establish neither how long it remained secret nor when it was first disclosed publicly.

Method and scope

Four ordered milestones with no time scale. Information shared in 2009 concerns tax matters broadly; cum-cum reassessment proposals are documented from 2017. May 2017 dates the start of the regular exchanges reported by ESMA; the Senate gives only the year of the earliest reassessments it mentions. Retrospective reports issued in 2020 and 2022 document earlier actions while leaving the date of their first public disclosure open.

The early audits raise a question of coverage: how much of the activity had they examined? An investigation can cover one institution, certain years and particular instruments while other transactions require further scrutiny. Assessing the tax response calls for comparing the audited activity with the transactions at issue.

An agency’s knowledge cannot automatically be assigned to every political office or bank executive. Establishing that a minister, senior management team or board received a particular warning requires additional evidence: a briefing, minutes, correspondence, a decision or verifiable testimony. The records assembled for this article date institutional actions. They do not reconstruct every route through which information travelled internally.

Autumn 2018 gives the issue a shared public identity

On 18 October 2018, the CumEx Files brought dividend-arbitrage arrangements to international public attention. CORRECTIV describes a collaboration involving 38 reporters, 19 newsrooms and 12 countries, with Le Monde as the French partner. Credit for that original investigation belongs to its authors. This article brings their publications together with parliamentary, regulatory and judicial records available for examination. S04

The clearest documentary link to a subsequent action comes eleven days later. Crédit Agricole CIB’s settlement records a complaint filed with France’s National Financial Prosecutor’s Office, the PNF, on 29 October 2018, by counsel acting for Boris Vallaud and the Collectif des Citoyens en Bande Organisée. The agreement connects that step to Le Monde’s investigation. Here, a public document explicitly links publication to a judicial initiative. S09, paragraphs 7–8

At European level, Parliament adopted a resolution on 29 November 2018, asking the securities and banking authorities to investigate. ESMA published preliminary findings on 2 July 2019. Its report also records a follow-up letter from MEPs, dated 29 March, criticising what they considered an inadequate initial response. Public scrutiny was followed by a documented demand for institutional accountability. S05, paragraph 5 S07, pages 4–6

The change is easiest to understand in terms of scope. A tax audit examines a taxpayer. An international investigation can connect practices, intermediaries and national responses, turning separate cases into a common subject of debate. Readers and legislators can then compare situations that each tax administration might otherwise approach through its own files.

The earlier audits and the journalistic investigation operated at different scales. The French complaint and the European resolution provide two concrete traces of the sequence opened by the revelations, alongside tax cases already under way.

Trading data show movements; evidence must connect them

A securities regulator can observe orders, volumes, securities loans and settlement failures. Those observations can guide an investigation, but their meaning depends on the economic relationship between the trades. ESMA notes, for example, that spikes in securities lending around dividend dates may also reflect transactions involving voting rights at shareholder meetings. S01, paragraphs 113–115

Consider an investigation beginning with an unusual volume of shares on loan. The timing suggests a tax-related lead. Investigators still need to identify the counterparties, their tax residence, the recipient of the dividend and the contracts through which value is returned. The contract, payment and tax treatment must be connected. A single market record may contain only part of that relationship.

Establishing responsibility for particular people then requires records of how an arrangement was designed, who approved it and which information was available when the decision was made. Trading frequency and profitability can guide the search; internal records can establish the decisions actually taken.

Method and scope

An analytical view of records to connect, rather than an automatic procedure. Securities lending and changes in trading volumes have several possible uses. Tax residence, contracts, payments and decisions require additional evidence. The diagram neither assigns every record to one authority nor treats an unusual transaction as sufficient to establish individual responsibility.

The French cooperation described by ESMA becomes more specific in February 2019. The AMF supplied technical expertise, Euroclear data and information on trading desks that might be carrying out cum-cum transactions. A trading desk is a specialist team within a dealing room. The report documents targeted assistance while preserving the provisional nature of the suspicions. S01, paragraph 119

Information sharing itself had rules. In its September 2019 report, France’s National Assembly recalled that the AMF had to provide the tax authority, on request, with information held within its remit, without invoking professional secrecy. Yet the rapporteurs, Émilie Cariou and Pierre Cordier, criticised the absence of spontaneous disclosures to the tax administration. S06, II.I.A.1

That criticism needs to be read alongside ESMA’s account of regular exchanges. The documents may be describing different practices. Answering a request and volunteering a new lead are separate forms of cooperation; the periods and transactions covered may also differ. Their juxtaposition produces a specific evidential question: what was transmitted, who initiated the exchange and what followed? The public records consulted do not resolve that question trade by trade.

At European level, ESMA’s 2019 work examined the conditions under which information received from other securities regulators could be passed to tax authorities. The European Banking Authority announced an action plan in May 2020 covering, among other things, governance, anti-money-laundering controls and cooperation. Those documents identify institutional work to be done. The effectiveness of the resulting measures requires a separate assessment. S07, section 5.2 S08

Prosecutors request tax information in September 2020

The agreement signed by Crédit Agricole CIB in September 2025 clarifies the prosecutorial timeline. It records a PNF requisition to the tax authority on 17 September 2020, seeking information about the progress of audits. This predates the involvement of the specialist investigating service generally associated with late 2021. S09, paragraph 11

On 25 November 2021, the Directorate for National and International Audits, the DVNI, replied. According to the agreement’s account, the service reported that it had observed no cum-ex fraud in France and described ongoing cum-cum cases, including CACIB’s. This was the service’s assessment at that date, expressly distinguishing the two families of arrangements. S09, paragraphs 12–13

On 16 December 2021, prosecutors assigned the investigation to the financial judicial investigation service, the SEJF, subsequently referred to in the agreement as the National Anti-Fraud Office. The 2020 and 2021 steps performed different functions: a request for information, the tax administration’s reply and the appointment of investigators. S09, paragraph 16

The steps recorded in the agreement provide the dates for the intervals below. The assembled record leaves the intervening work to be documented separately.

Method and scope

l0g calculation using civil-date differences without double-counting endpoints: 29 October 2018 to 17 September 2020, 689 days; 17 September 2020 to 25 November 2021, 434 days; 25 November to 16 December 2021, 21 days. Total: 1,144 days. The three bars start at zero and share one scale. The dates come from paragraphs 7 and 11–16 of the agreement; the assembled record does not detail intervening work. Assessing the pace would require requests, replies, staffing decisions and evidential obstacles.

On 28 March 2023, searches at five financial institutions made the investigations highly visible. Le Monde documented the simultaneous operation. A search is a step in gathering evidence; the criminal responsibility of each entity or individual depends on the subsequent course of their own proceedings. S10

Audits, trading and legal changes run on overlapping calendars

Inside a bank, timelines also overlap. CACIB’s agreement describes the introduction in 2019 of internal rules restricting transactions around the ex-dividend date, following the first audits and the measure adopted in the Finance Act for 2019. It says the relevant activity subsequently became residual. The conduct described in the agreement covers 2013 to 2022. S09, paragraphs 37–39

That wording is more informative than a single supposed shutdown date. An internal restriction can reduce activity while leaving some transactions in place. The agreement supplies no annual series with which to measure that reduction here. It does, however, distinguish residual activity after 2019 from its complete disappearance in that year.

The document also separates the scope of the tax audits from that of the judicial investigation. The latter identified transactions involving years or instruments the tax authority had not examined. A tax settlement dated 2 April 2021 forms part of that history; the agreement concerning the criminal proceedings would be signed in 2025. S09, paragraphs 14 and 32

Differences in scope help explain why a case can remain open after an initial settlement. Later work may address additional trades, other years or a different legal issue. A procedure’s result can only be assessed against the facts it actually covered.

Method and scope

Three acts with separate purposes: CACIB’s tax settlement of 2 April 2021, the administrative-guidance ruling of 8 December 2023 and CACIB’s corporate settlement signed on 5 and approved on 8 September 2025. The French Banking Federation’s challenge concerned guidance in a separate case. The columns are not mandatory stages of one procedure; an approved CJIP remains legally distinct from a conviction.

The applicable law was also contested. On 8 December 2023, France’s Conseil d’État quashed an expanded administrative interpretation challenged by the French Banking Federation: the guidance had added to the wording of Article 119 bis then in force. The ruling preserved the cases covered by Article 119 bis A and the abuse-of-law procedure. S11, points 3–8

This is a material counterargument to a story in which the administration always possessed one straightforward rule immediately applicable to every transaction. The legal basis it chose could be challenged successfully. The 2023 ruling addressed that administrative extension; the other grounds it preserved still required examination in individual cases.

A rigorous account has to keep the transactions, the available enforcement tools and the courts’ limits on their use in the same frame. A legislative amendment may strengthen future controls while earlier trades remain governed by the law applicable at the time. Tracing successive versions of the rules is therefore as important as dating the transactions themselves.

Public settlements, with part of the record still missing

CACIB’s agreement was signed on 5 September 2025 and approved on 8 September. The agreement with HSBC Bank plc was concluded on 6 January 2026 and approved on 8 January. The PNF’s statement concerns intragroup transactions in 2014–2019 involving its Paris branch. These are separate milestones involving specified legal entities and conduct. S12 S13

A convention judiciaire d’intérêt public, or CJIP, is a French corporate settlement mechanism that can resolve criminal proceedings subject to conditions. Judicial approval entails no declaration of guilt and does not have the effects of a criminal conviction, as CACIB’s agreement expressly states. The PNF also emphasises that this agreement does not address the criminal position of third parties, including individuals. S09, paragraphs 60–61 S12

Such agreements make facts and parts of an earlier chronology publicly accessible. Their nature matters when reading them. The public has a published agreement, while the contracts, tax correspondence and full investigative file remain largely beyond the materials assembled here. CACIB’s agreement also describes an internal investigation conducted with outside counsel and parallel checks by prosecutors and investigators. The full internal report was not obtained for this analysis. S09, paragraphs 17–20

Reform follows its own timetable. Guidance published in France’s official tax bulletin on 16 March 2026 explains the external cum-cum provisions introduced by the Finance Act for 2025, which took effect on 1 January 2026. In a reply published by the Senate on 15 October 2026, the ministry reported €4.5 billion in additional tax notified following earlier reassessments. That reply does not supply the corresponding amount actually collected. S15 S16

The figure describes tax claims announced by the administration. For the history of warnings, the question remains how available information became action covering the relevant transactions.

The reconstructed chronology already supports a clear conclusion. French tax action preceded the 2018 revelations; technical cooperation had an earlier history; and a documented prosecutorial step in 2020 came before investigators were assigned in late 2021. It also shows responses with different purposes: gathering intelligence, challenging tax treatment, collecting evidence, revising the law and reaching a corporate settlement.

The precise circulation of warnings, the decisions taken upon receiving them and the transactions left outside the early audits still require documentation. On those questions, the decisive evidence would be correspondence, minutes or audit files connecting a specific piece of information to a decision. That is the level at which an institutional history can become an investigation into established responsibility.

Scope of this investigation

Documentary analysis with an evidence cut-off of 27 October 2026. Earlier events are sometimes known through later published accounts; the distinction appears in the source notices. Statements by the AMF, tax administration and parliamentary rapporteurs are attributed to their authors. No interviews, hearings or requests for comment were conducted for this article. Non-public underlying records were not obtained. Open questions are leads for further verification, rather than implied allegations.

Further reading

• Cum-cum: the dividend mechanism and the sharing of a tax advantage.
• Euroclear: the vault at the centre of European financial flows.
• Banks: the cost of the December snapshot.

Sources

The notices distinguish an event’s date from the publication describing it. Each reference identifies the passages used, their scope and the limits of the material consulted.

1. S01 · ESMA · 23 September 2020 · Accessed: 2026-10-27Final Report on Cum/Ex, Cum/Cum and withholding tax reclaim schemes
   Passages and scope

   Printed page 28, paragraphs 110–119; executive summary, pages 7–8.

   AMF information sharing in 2009, regular exchanges from May 2017 and targeted assistance in February 2019.

   ESMA’s account of national authorities’ responses, not an independent audit of the 2009 exchanges. The 2009 information concerns tax matters broadly. Page 28, paragraphs 110–119, rendered and inspected; no claim to have read all 71 pages.

2. S02 · Deutscher Bundestag · 20 June 2017 · Accessed: 2026-10-27Drucksache 18/12700 : rapport de la quatrième commission d’enquête
   Passages and scope

   Printed pages 114–115: the letters of 2 August and 20 December 1978.

   German precedent: tax credit for a resident shareholder and warnings to banks.

   Pages 114–115 rendered and inspected. The report recounts documents from 1978; it does not establish a universal starting date for cum-cum. Minority opinions are outside the evidence used here.

3. S03 · Sénat, commission des finances · 25 October 2022 · Accessed: 2026-10-27Fraude et évasion fiscales : faire les comptes et intensifier la lutte, rapport n°72
   Passages and scope

   Part IV.A.2, passage on CumEx Files and proposed cum-cum reassessments.

   Cum-cum reassessment proposals sent from 2017, before the 2018 revelations.

   Information supplied by the tax administration to the rapporteur. Individual reassessment proposals are outside the public material assembled here. Report dated 25 October 2022; web page updated 7 April 2023.

4. S04 · CORRECTIV et partenaires des CumEx Files · 18 October 2018 · Accessed: 2026-10-27The CumEx-Files
   Passages and scope

   Project introduction, The Cooperation and partner list.

   Publication on 18 October 2018; 38 reporters, 19 newsrooms and 12 countries.

   The consortium’s original account of its own work. The leaked underlying records were not independently consulted for this article. The page’s aggregate fiscal-loss estimates are not used.

5. S05 · Parlement européen · 29 November 2018 · Accessed: 2026-10-27Résolution P8_TA(2018)0475 sur le scandale des CumEx Files, 2018/2900(RSP)
   Passages and scope

   Paragraphs 5, 7, 10 and 11.

   Requests to ESMA and the EBA, supervision and information sharing.

   A political resolution, legally distinct from a judgment. Its combined introductory description of cum-cum and cum-ex is not used as a technical definition of either mechanism.

6. S06 · Assemblée nationale, Émilie Cariou et Pierre Cordier · 25 September 2019 · Accessed: 2026-10-27Rapport d’information n°2252 sur le bilan de la lutte contre les montages transfrontaliers
   Passages and scope

   Part II.I.A.1, AMF cooperation with the tax administration.

   The distinction between information supplied on request and spontaneous disclosure.

   The criticism of spontaneous information sharing is attributed to the rapporteurs, alongside ESMA’s account of regular exchanges. General information-request statistics are not treated as a count of cum-cum cases.

7. S07 · ESMA · 2 July 2019 · Accessed: 2026-10-27Preliminary findings on multiple withholding tax reclaim schemes
   Passages and scope

   Printed pages 4–6 and section 5.2, pages 22–24.

   The parliamentary follow-up of 29 March 2019 and information received from other European authorities.

   Pages 4–6 and 22–24 rendered and inspected; page 24 is blank. Legal observations are presented as of 2019 and are not automatically carried forward to 2026.

8. S08 · Autorité bancaire européenne, communiqué repris par la Banque centrale de Hongrie · 12 May 2020 · Accessed: 2026-10-27EBA publishes its inquiry into dividend arbitrage trading schemes and announces a 10-point action plan
   Passages and scope

   Statement dated 12 May 2020, hosted by the Hungarian central bank.

   Governance, anti-money-laundering controls and cooperation.

   An institutional republication of the EBA statement. The direct EBA page was unavailable during the check. Announcing an action plan and establishing its effectiveness are separate questions.

9. S09 · Parquet national financier et Crédit Agricole CIB · 5 September 2025 · Accessed: 2026-10-27Convention judiciaire d’intérêt public Crédit Agricole CIB
   Passages and scope

   Printed pages 2–3, paragraphs 7–20; pages 5–6, paragraphs 28–41; page 8, paragraphs 60–61. PDF page positions are one page higher.

   Complaint, requisition, DVNI reply, SEJF assignment, internal restrictions and the agreement’s legal limits.

   The signed negotiated agreement is not a criminal conviction. Printed pages 2–3, 5–6 and 8 rendered and inspected; PDF positions are one page higher. The underlying correspondence, contracts and full internal investigation report were not obtained separately.

10. S10 · Le Monde, Anne Michel, Jérémie Baruch et Maxime Vaudano · 28 March 2023 · Accessed: 2026-10-27Cinq établissements visés par des perquisitions dans une affaire de fraude fiscale
    Passages and scope

    Accessible paragraphs concerning searches on 28 March 2023.

    Simultaneous searches at five institutions on 28 March 2023.

    Published 28 March 2023, updated 15 May 2023. Only the accessible part of the subscription article was consulted. Searches concern evidence gathering and do not determine guilt.

11. S11 · Conseil d’État · 8 December 2023 · Accessed: 2026-10-27Décision n°472587, Fédération bancaire française
    Passages and scope

    Points 3–8 and operative ruling.

    Annulment of an interpretation exceeding the wording then in force.

    The ruling concerns the guidance and legislation applicable at the time. It preserves Article 119 bis A and abuse-of-law grounds, without generally validating individual cum-cum transactions.

12. S12 · Parquet national financier · 8 September 2025 · Accessed: 2026-10-27Communiqué sur la CJIP Crédit Agricole CIB
    Passages and scope

    Single-page PNF statement, visually reviewed.

    CACIB agreement signed on 5 and approved on 8 September 2025; third parties’ position remains separate.

    The single-page prosecutor’s statement was inspected. Dates of signature and approval are distinct. Payment obligations, amounts received and aggregate loss estimates remain separate quantities.

13. S13 · Parquet national financier · 8 January 2026 · Accessed: 2026-10-27Communiqué sur la CJIP HSBC Bank plc
    Passages and scope

    Single-page PNF statement, visually reviewed.

    HSBC Bank plc agreement signed on 6 and approved on 8 January 2026; intragroup transactions during 2014–2019.

    The single-page statement was inspected. The entity is HSBC Bank plc and the transactions concern its Paris branch. No claim relies on unexamined pages of the full HSBC agreement.

14. S14 · Conseil d’État · 27 January 2025 · Accessed: 2026-10-27Avis sur le renforcement de la retenue à la source pour les arbitrages de dividendes
    Passages and scope

    Introduction and points 1–2 of the opinion.

    Mechanism and the measure introduced by Article 36 of the Finance Act for 2019.

    The government’s request and the Conseil d’État’s own opinion are kept distinct. An opinion on draft legislation does not replace the enacted law.

15. S15 · Direction générale des finances publiques · 16 March 2026 · Accessed: 2026-10-27Actualité BOFiP : modalités pratiques, cum-cum externes, article 96 de la loi de finances pour 2025
    Passages and scope

    Official announcement and effective date.

    Publication of guidance and effective date of the external cum-cum provisions.

    Guidance published on 16 March 2026; the provisions concerned took effect on 1 January 2026. Publication alone supplies no measurement of effectiveness.

16. S16 · Sénat / ministère de l’Action et des Comptes publics · 15 October 2026 · Accessed: 2026-10-27Question écrite n°07856 : Contrôle des arbitrages de dividendes
    Passages and scope

    Ministerial answer, Senate Official Journal, 15 October 2026, page 4975.

    Government statement of €4.5 billion in additional tax notified.

    The ministry’s answer was published on 15 October 2026, following a question filed on 26 February. Additional tax notified is attributed to the ministry and kept distinct from money collected. The senator’s assertions are not adopted as ministry findings.