{
  "url": "https://openlegislation.uk/eu-regulation-2017-566/introduction",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-566/introduction.json",
  "legislation": "eur/2017/566",
  "legislation_title": "Commission Delegated Regulation (EU) 2017/566 of 18 May 2016 supplementing Directive 2014/65/EU of the European Parliament and of the Council on markets in financial instruments with regard to regulatory technical standards for the ratio of unexecuted orders to transactions in order to prevent disorderly trading conditions (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-566",
  "path": "introduction",
  "kind": "introduction",
  "number": null,
  "heading": "Introductory text",
  "text": "Commission Delegated Regulation (EU) 2017/566\nof 18 May 2016\nsupplementing Directive 2014/65/EU of the European Parliament and of the Council on markets in financial instruments with regard to regulatory technical standards for the ratio of unexecuted orders to transactions in order to prevent disorderly trading conditions\n(Text with EEA relevance)\nTHE EUROPEAN COMMISSION,\nHaving regard to the Treaty on the Functioning of the European Union,\nHaving regard to Directive 2014/65/EU of the European Parliament and of the Council of 15 May 2014 on markets in financial instruments and amending Directive 2002/92/EC and Directive 2011/61/EU, and in particular Article 48(12)(b) thereof,\nWhereas:\n(1)\nTrading venues should have a number of systems, procedures and arrangements in place to ensure that algorithmic trading systems cannot create or contribute to disorderly trading conditions including systems to monitor and, where appropriate, limit the ratio of unexecuted orders to transactions.\n(2)\nTaking into account their nature, voice trading systems should be exempt from the scope of this Regulation which should only apply to trading venues operating electronic continuous auction order book or quote-driven or hybrid trading systems.\n(3)\nDirective 2014/65/EU extends the requirements relating to the determination of the ratio of unexecuted orders to transactions to multilateral trading facilities and organised trading facilities. It is therefore important that those venues are also within the scope of this Regulation.\n(4)\nTrading venues should calculate the ratio of unexecuted orders to transactions effectively incurred by their members or participants at the level of each financial instrument traded on them in order to ensure effectively that the ratio does not lead to excessive volatility in that instrument.\n(5)\nIn order to ensure sufficient harmonisation across the Union of the arrangements to prevent disorderly trading conditions through the limitation of the ratio between unexecuted orders and transactions, a clear methodology to calculate the ratio of unexecuted orders to transactions with respect to all market participants should be laid down.\n(6)\nThe meaning of certain essential parameters to be used for the calculation of the ratio of unexecuted orders to transactions should be clarified.\n(7)\nThe calculation of the ratio of unexecuted orders to transactions entered into the system by a member or participant should be supported by an adequate observation period. On that basis, the calculation period of the effective ratio of unexecuted orders to transactions should not be longer than a trading session. However, trading venues should be allowed to set out shorter observation periods in case such shorter observation periods would contribute more effectively to maintain orderly trading conditions.\n(8)\nFor reasons of consistency and in order to ensure the smooth functioning of the financial markets, it is necessary that the provisions laid down in this Regulation and the related national provisions transposing Directive 2014/65/EU apply from the same date.\n(9)\nThis Regulation is based on the draft regulatory technical standards submitted by the European Securities and Markets Authority to the Commission.\n(10)\nThe European Securities and Markets Authority has conducted open public consultations on the draft regulatory technical standards on which this Regulation is based, analysed the potential related costs and benefits and requested the opinion of the Securities and Markets Stakeholder Group established by Article 37 of Regulation (EU) No 1095/2010 of the European Parliament and of the Council,\nHAS ADOPTED THIS REGULATION:",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "C",
      "label": "C1",
      "text": "The “appropriate regulator” has power to make such provision as they consider appropriate by means of an instrument in writing to prevent, remedy or mitigate any failure of the provisions of this Regulation to operate effectively or any other deficiency arising from the withdrawal of the United Kingdom from the EU, see The Financial Regulators' Powers (Technical Standards etc.) (Amendment etc.) (EU Exit) Regulations 2018 (S.I. 2018/1115), regs. 2, 3, Sch. para. 26 (with saving on lP completion day by S.I. 2019/680, regs. 1(2), 11; 2020 c. 1, Sch. 5 para. 1(1))"
    },
    {
      "type": "C",
      "label": "C2",
      "text": "Regulation: power to modify conferred (11.7.2023) by Financial Services and Markets Act 2023 (c. 29), ss. 3, 86(3), Sch. 1 Pt. 3; S.I. 2023/779, reg. 2(d)"
    },
    {
      "type": "footnote",
      "label": "f1",
      "text": "OJ L 173, 12.6.2014, p. 349."
    },
    {
      "type": "footnote",
      "label": "f2",
      "text": "Regulation (EU) No 1095/2010 of the European Parliament and of the Council of 24 November 2010 establishing a European Supervisory Authority (European Securities and Markets Authority), amending Decision No 716/2009/EC and repealing Commission Decision 2009/77/EC (OJ L 331, 15.12.2010, p. 84)."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/566/introduction",
    "retrieved_at": "2026-11-01T14:45:05.916972+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}