# Article 16 — References to trading day and daily trading hours **Commission Delegated Regulation (EU) 2017/587 · binding · OJ L 87, 31.3.2017 · dated 14 Jul 2016 [in force]** *In force · Consolidated version of 2 March 2026 · Checked against EUR-Lex on 26 Oct 2026 · [Official source](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02017R0587-20260302)* 1. A reference to a trading day in relation to a trading venue shall be a reference to any day during which that trading venue is open for trading. 2. A reference to daily trading hours of a trading venue or an investment firm shall be a reference to the hours which the trading venue or investment firm establishes in advance and makes public as its trading hours. 3. A reference to the opening of the trading day at a given trading venue shall be a reference to the commencement of the daily trading hours of that trading venue. 4. A reference to the end of the trading day at a given trading venue shall be a reference to the end of the daily trading hours of that trading venue. **CHAPTER IV — PROVISIONS COMMON TO PRE-TRADE AND POST-TRADE TRANSPARENCY CALCULATIONS**