At 6:10 p.m. in Istanbul, Borsa İstanbul’s equity market is shut. For most of the market, that is the end of trading. However, for lawyers, investment banking partners, and major corporate shareholders who live inside accelerated equity deals, it is the starting gun. When the screens go dark in Istanbul, London is still wide awake at 4:10 p.m., and New York is settling into the middle of its trading day. So, a single transaction can keep moving across three time zones long before Turkish markets open again.
An accelerated bookbuild (“ABB”) is “a way of placing shares with investors in a short space of time once the announcement of the proposed fundraising has been released with little or no marketing.”[1] Overnight, a Turkish cross-border ABB activates three legal systems at once: Turkish disclosure rules,[2] UK/EU market-abuse and institutional-offer regimes,[3] and U.S. private-placement and anti-fraud rules[4] where qualified institutional buyers’ (“QIB”) capital comes in. There is no global rulebook holding them together.[5] One misstep before the market reopens, and the speed that made the deal possible becomes the source of its liability.
I. Overnight Prospectus Problem
A prospectus is the regulator-approved disclosure document given to potential investors before securities are offered to the public or admitted to trading, describing the securities, the issuer, and the attendant risks so that investors can make an informed assessment. The prospectus is the slowest form of legal discipline capital markets have as it demands full disclosure, regulator review, and a liability structure built around retail investors. An ABB has no room for that timetable. Yet in Türkiye, just as in the UK, EU, and U.S., the faster route does not mean abandoning disclosure, it means moving into a different regime. Public offerings require a prospectus under the Share Communiqué, while Article 13 permits listed companies to increase capital through share sales that bypass the public-offering process.[6] Even so, these sales require an issue certificate approved by the Capital Markets Board (also known as “Sermaye Piyasası Kurulu”) (“SPK”), and when executed on the Borsa İstanbul’s relevant market or platform, pricing and tradability fall under the exchange rulebook rather than a retail prospectus regime.[7]
When it comes to existing-share blocks, Borsa İstanbul’s wholesale procedures are the operational backbone. They cover sales of listed shares held by existing shareholders and capital increases via private placement.[8] An application to Borsa İstanbul is required, along with a Central Securities Depository and Trade Repository of the Turkish Capital Markets (also known as “Merkezi Kayıt Kuruluşu”) (“MKK”) balance report confirming whether shares are tradable, a Public Disclosure Platform (also known as “Kamuyu Aydınlatma Platformu”) (“KAP”) disclosure on the application day, and execution no earlier than the business day following disclosure once exchange approval is in hand.[9] Trades are expected to clear through the Borsa İstanbul equity settlement process by default, but parties can step outside it, at which point the exchange, Takasbank,[10] and MKK disclaim liability for settlement.[11]
The UK and EU reach similar practical results, but through different paths. Since 19 January 2026, the Public Offers and Admissions to Trading Regulations make public offers in the UK unlawful unless the offer is of a specified kind or a general exception applies, and Financial Conduct Authority (“FCA”) materials use qualified-investor-only offers as an example of a Schedule 1 exempt offer.[12] The EU takes a parallel but structurally distinct approach, with Article 1(4) of the Prospectus Regulation preserving the classic institutional exemptions, qualified-investor-only offers, high-denomination and limited-offeree structures.[13] The U.S. relies on its familiar pairing of Rule 144A for QIB resales and Regulation S for offshore sales.[14]
Liability does not stop where the prospectus ends. Rule 144A itself says it relates only to Section 5, the Securities Act’s registration requirement, which obliges securities to be registered before they are offered or sold, and not to anti-fraud provisions.[15] Section 11 of the Securities Act attaches to false or misleading registration statements, which means it is not the organising liability theory for an exempt ABB.[16] But Rule 10b-5[17] and Section 10(b)[18] remain fully live, and that is what gives the overnight disclosure package so much weight. In practice, lawyers and auditors protect an offering memorandum by going through in detail. They back it up with comfort letters, management certifications, and standard negative-assurance letters, essentially a formal statement confirming that they did not find anything materially inaccurate or misleading. None of these are statutory filings. Instead, they serve as the private offering’s defensive shield, often pulled together in a matter of hours rather than months.[19]
II. Wall-Crossing Across Borders
Before an ABB formally launches, banks need to check if the market is there. That instinct leads to a legally sensitive step in the process: bringing selected investors over the wall. In form, wall-crossing is relatively straightforward. The disclosing participant checks whether the investor is willing to receive confidential information, flags that the information may constitute inside information, secures confidentiality and no-trade commitments, and finally tests the waters.[20] This is the moment when the deal begins to create a defined and controlled circle of insiders. Both European Securities and Markets Authority’s (“ESMA”) approach to Article 11[21] and the FCA’s UK Market Abuse Regulation (“MAR”) guidance[22] treat market soundings as a formal framework for legitimate disclosure before an announcement, rather than as an extension of ordinary market conversations.
MAR is primarily instrument-focused rather than geographically focused. ESMA is clear that Article 11 market soundings concern potential transactions in instruments falling within the scope of Article 2, instruments admitted to trading, traded, or requested for admission on a regulated market, together with certain linked instruments whose price or value depends on or affects an in-scope instrument.[23] A call run from London to Dubai or Riyadh can still sit comfortably inside the UK or EU market sounding regime if the instrument, or a linked instrument, carries the required venue nexus. The reverse is equally true: not every Turkish equity block handled by a London desk becomes a MAR transaction simply because London bankers are involved. The first real legal question is always the instrument perimeter.
This is the cross-border complication of ABBs. One institutional investor call can simultaneously engage Turkish confidentiality and disclosure planning, UK or EU MAR process discipline where relevant, and U.S. anti-fraud and material non-public information sensitivities if the distribution reaches QIB investors, all at once. The Article 11(4) safe harbour is not automatic; it is available only where the prescribed process is followed. This includes assessing in advance whether the information amounts to inside information, giving the recipient the required disclosures, proper recordkeeping, and later cleansing once the information ceases to be inside information.[24] An accelerated timetable does not make these requirements any less important. On the contrary, it increases the need for a disciplined process because once a leak occurs, there is no practical room to reconstruct a process that was not followed in the first place.
In Türkiye, KAP adds another layer of urgency. Under SPK’s special-circumstances framework, inside information must generally be disclosed without delay. Disclosure may be postponed, however, where this is necessary to protect the issuer’s legitimate interests, the delay is unlikely to mislead the public, and confidentiality can be preserved.[25] That makes confidentiality one of the legal conditions that allows the issuer to postpone public disclosure. If a wall-crossed investor in London or New York leaks before launch, the issuer can find itself forced into an unplanned KAP announcement.[26] That, in turn, may weaken the issuer’s position on pricing, raise concerns about equal access to information, and disrupt the carefully managed sequence of market sounding, book launch and execution.
III. Risk Allocation After Midnight
As the order book takes shape, the focus begins to move from securities regulation to contractual risk allocation. In a seller block trade or a privately placed issuance of new shares, the block trade agreement or share purchase agreement determines who bears the consequences if something goes wrong between pricing and settlement.[27]
The relevant Borsa İstanbul documentation identifies some of the basic factual assumptions underlying the transaction. The wholesale transaction application requires confirmation that the shares are not subject to any encumbrance restricting their transfer or circulation and asks the parties to specify whether settlement will occur inside or outside the exchange process.[28] Market-standard ABB documentation develops this framework. Sellers and, where applicable, issuers typically give representations concerning title to the shares, authority and capacity, corporate approvals, the accuracy of the disclosure materials, compliance with selling restrictions and the absence of material omissions.[29]
The banks will also require a range of conditions to be satisfied before completion, including the necessary approvals, legal opinions, bringdown confirmations and the continued accuracy of the representations at both pricing and closing.[30] Indemnities complete the allocation of risk by determining the extent to which losses arising from investor claims, disclosure deficiencies or regulatory scrutiny are passed back to the seller or issuer.
A recent English case provides a useful illustration of how these provisions may be interpreted in practice. In BM Brazil I Fundo de Investimento em Participações Multistrategia v Sibanye BM Brazil (Pty) Ltd (“BM Brazil”),[31] the Commercial Court offered unusually practical guidance on the interpretation of material adverse change and material adverse effect provisions in share purchase agreements. The Court suggested that materiality in an SPA context might begin with a reduction of around 15% to 20% in equity value.[32] It also treated “material” as requiring something significant or substantial;[33] rejected reliance on later “revelatory” events that simply brought an existing problem to light;[34] and held that whether an event “would reasonably be expected” to have the relevant effect should be assessed objectively and prospectively at the time the termination right is exercised.[35] This underscores that material adverse change language should not simply be lifted from acquisition or underwriting precedents. It needs to be tested against the specific risks that could disrupt pricing, closing or settlement in a transaction expected to be completed the following morning.
In Turkish cross-border transactions, the point of failure may be operational rather than connected to the underlying business. A sharp overnight movement in the exchange rate, a mismatch in funding arrangements or poor coordination between the Turkish share settlement and the offshore payment process may prevent completion, even where the issuer’s financial position and enterprise value remain unchanged. Applying the reasoning in BM Brazil, such events should not automatically amount to a material adverse change unless the clause has been drafted specifically to cover settlement-system disruption, funding failure or similar execution risks. Otherwise, a broadly framed termination right may be introduced into a transaction affected by execution mechanics rather than any decline in enterprise value. This is not a direct holding of BM Brazil, but the case has a broader drafting implication when read in the context of Turkish settlement mechanics, which ordinarily requires the shares and purchase price to be exchanged two business days after the trade and allows the parties to settle either through the exchange or outside it.
Lock-up arrangements require the same level of care. In an ABB, the commitment given by the remaining major shareholders not to sell further shares may provide greater support for investor confidence than the discount offered on the shares. In the Turkish context, however, this assurance must be effective at both the contractual and operational levels. The contractual undertaking may be governed by English or New York law and enforceable by the banks, but the mechanics of any subsequent transfer will continue to depend on MKK and Borsa İstanbul.[36] The parties must also consider whether the undertaking is material enough to trigger a KAP disclosure. Therefore, the practical challenge is to structure the contractual commitment, the local transfer process and the applicable disclosure requirements without creating any legal or operational gap between them.
IV. Settlement, Clearance and Next Steps
By 7:30 a.m. in Istanbul, the transaction generally moves to its implementation phase. The remaining tasks are to ensure that the KAP announcement and other public statements are consistent, confirm the final price, determine the settlement method and ensure that the securities transfer and payment can be completed together. Settlement in the Turkish market generally occurs two business days after the trade. Takasbank oversees the corresponding movements of cash and securities, ordinarily on a delivery-against-payment basis,[37] while MKK acts as the central electronic depository in which securities are recorded and transferred. MKK also provides matching infrastructure for off-exchange securities transfers completed independently of payment.[38]
The legal risk during the period between pricing and settlement should not be underestimated. Any disclosure defect discovered in that period may require corrective disclosure, renewed investor consent or confirmation, an assessment of the closing conditions and consideration of the contractual indemnities. Hence, an ABB may appear complete once allocations are confirmed, but its most legally sensitive period often begins immediately afterwards.
V. Conclusion
The ABB is one of the fastest ways to sell listed shares, but it is also legally demanding. Its speed comes from compressing disclosure, diligence, market-abuse controls and settlement planning into hours. This matters increasingly for Turkish issuers, major shareholders and institutional investors as ABBs provide an important route to international institutional capital. These transactions bring together Borsa İstanbul rules, MKK settlement mechanics and SPK disclosure requirements with UK/EU market-abuse standards and U.S. anti-fraud considerations. The success of the transaction depends on bringing those requirements together accurately and efficiently without losing sight of the practical demands of execution.
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[1] LexisNexis, “Equity capital markets—glossary of terms”, https://www.lexisnexis.co.uk/legal/guidance/equity-capital-markets-glossary-of-terms, accessed 29 June 2026.
[2] Communiqué on Material Events Disclosure (II-15.1), Official Gazette No. 28891, 23 January 2014 (Türkiye); Capital Markets Board of Türkiye, “Guide on Material Events Disclosure” (“CMB Guide”), https://spk.gov.tr/data/61e36ca51b41c61270320820/0dc4659f7005c7d2bdc5f151a7014ba8.pdf, accessed 29 June 2026.
[3] Market Abuse Regulation; Regulation (EU) 2017/1129 – the EU Prospectus Regulation.
[4] Rule 144A (17 C.F.R. § 230.144A); Regulation S of the US Securities Act of 1933.
[5] LexisNexis, “Accelerated Bookbuild” (Legal Glossary) https://www.lexisnexis.com/en-gb/legal/glossary/accelerated-bookbuild, accessed 29 June 2026 (noting that an ABB is “a market practice term, not defined in legislation or case law”).
[6] Share Communiqué (VII-128.1), Official Gazette No. 28685, 22 June 2013, art. 13.
[7] Borsa İstanbul, “Procedure on Wholesale Transactions Procedures and Principles” (“Wholesale Transactions”), https://www.borsaistanbul.com/files/wholesale-transactions-procedures-and-principles.pdf, accessed 29 June 2026.
[8] Id., p. 3.
[9] Id., pp. 3-4, 6.
[10] Takasbank (İstanbul Takas ve Saklama Bankası A.Ş.) is Türkiye’s central clearing, settlement, and custody institution for the capital markets, responsible for the clearing and settlement of exchange transactions.
[11] Wholesale Transactions, p. 7.
[12] Public Offers and Admissions to Trading Regulations 2024 (SI 2024/105), https://www.legislation.gov.uk/uksi/2024/105/made, accessed 29 June 2026; Financial Conduct Authority, “PRM 1 Introduction, application and prospectus requirement” https://handbook.fca.org.uk/handbook/prm1?date=15-06-2026&timeline=true, accessed 29 June 2026, PRM 1.1.2.
[13] Regulation (EU) 2017/1129 of the European Parliament and of the Council of 14 June 2017 on the prospectus to be published when securities are offered to the public or admitted to trading on a regulated market, and repealing Directive 2003/71/EC, https://eur-lex.europa.eu/eli/reg/2017/1129/oj/eng, accessed 29 June 2026, art. 1(4).
[14] Bloomberg Law, “Capital Markets, Overview – Rule 144A/Reg S Debt Offering (Practice Points)”, https://www.bloomberglaw.com/external/document/X9GS3MHO000000/capital-markets-overview-rule-144a-reg-s-debt-offering-practice-, accessed 29 June 2026; Thomson Reuters Practical Law, “Rule 144A Offerings Toolkit”, https://uk.practicallaw.thomsonreuters.com/2-578-8007?transitionType=Default&contextData=(sc.Default)&firstPage=true, accessed 29 June 2026.
[15] Rule 144A itself says it relates only to Section 5 and not to anti-fraud provisions; Rule 144A, https://www.ecfr.gov/current/title-17/chapter-II/part-230/section-230.144A, accessed 29 June 2026, Preliminary Notes, 1.
[16] 15 U.S.C. § 77k (Securities Act), https://www.govinfo.gov/content/pkg/COMPS-1884/pdf/COMPS-1884.pdf, accessed 29 June 2026, Section 11.
[17] 17 C.F.R. § 240.10b-5.
[18] 15 U.S.C. § 78j(b) (Securities Exchange Act), Section 10(b).
[19] Gary M. Lawrence, “In Search of Reasonableness: The Exercise of Professional Judgment by Underwriters and Its Implication for Judicial Determinations of Reasonableness”, American Bar Association Business Law Section, 2022 (“Lawrence”), https://businesslawtoday.org/2022/12/underwriters-professional-judgment-implication-judicial-determinations-reasonableness/, accessed 29 June 2026.
[20] European Securities and Markets Authority, “Final Report – Guidelines on the Market Abuse Regulation – market soundings and delay of disclosure of inside information”, 2016, https://www.esma.europa.eu/sites/default/files/library/2016-1130_final_report_on_mar_guidelines.pdf, accessed 29 June 2026.
[21] Regulation (EU) No 596/2014 of the European Parliament and of the Council of 16 April 2014 on market abuse (market abuse regulation) and repealing Directive 2003/6/EC of the European Parliament and of the Council and Commission Directives 2003/124/EC, 2003/125/EC and 2004/72/EC (“Regulation (EU) No 596/2014”), https://eur-lex.europa.eu/eli/reg/2014/596/oj/eng, accessed 29 June 2026, art. 11.
[22] Financial Conduct Authority, “Market Abuse Regulation”, https://www.fca.org.uk/markets/market-abuse/regulation, accessed 29 June 2026.
[23] Regulation (EU) No 596/2014, art. 11.
[24] Stefano Lombardo and Federico M. Mucciarelli, “Market Soundings: The Interaction between Securities Regulation and Company Law in the United Kingdom and Italy”, ECGI – Law Working Paper No. 362/2017, 2017, pp. 320-327.
[25] CMB Guide, pp. 18-20.
[26] Id., p. 20.
[27] Association for Financial Markets in Europe, “Model Block Trade Agreement (Without Backstop)” (“AFME”), https://www.afme.eu/media/anbb21uq/afmeecmsfdmodelblocktradeagreementnonbackstop.pdf, accessed 29 June 2026, art. 3.
[28] Wholesale Transactions, p. 8.
[29] AFME, Annex B.
[30] Lawrence.
[31] BM Brazil I Fundo De Investimento Em Participacoes Multistrategia & Ors v Sibanye BM Brazil (Pty) Ltd & Anor [2024] EWHC 2566 (Comm) (10 October 2024), https://www.bailii.org/ew/cases/EWHC/Comm/2024/2566.html, accessed 29 June 2026.
[32] Id., paras. 253-255.
[33] Id., paras. 250-251.
[34] Id., paras. 229-240.
[35] Id., paras. 224-225.
[36] AFME, art. 8.
[37] Borsa İstanbul, “Settlement Principles”, https://www.borsaistanbul.com/en/markets/equity-market/settlement-principles, accessed 29 June 2026.
[38] Merkezi Kayıt Kuruluşu, “Borsa İstanbul Pay Piyasası” (Borsa İstanbul Equity Market), https://www.mkk.com.tr/saklama-hizmetleri/piyasalar-ve-platformlar/borsa-istanbul-pay-piyasasi, accessed 29 June 2026.
