Exchanges and Market Structure: Rules and Plumbing — 2026-09-13
This week saw significant volatility in market infrastructure, highlighted by technical outages at the Bombay Stock Exchange (BSE) during critical derivatives expiry sessions and a major capital raise by Deutsche Börse. Meanwhile, the SEC continues to shape the regulatory landscape with proposed amendments to Regulation NMS and preparations for 24-hour trading, while dark pool activity remains elevated at over 40% of US equity volume.
Exchanges and Market Structure: Rules and Plumbing — 2026-09-13
Top developments
BSE Technical Glitches Disrupt Sensex Expiry Trading
On September 10, 2026, the Bombay Stock Exchange (BSE) suffered a brief technical outage that disrupted futures and options (F&O) trading during the weekly Sensex expiry day. The glitch affected specific segments of the cash market and caused delayed price updates and order placement failures for brokers, including major retail player Zerodha. The exchange resolved the issue shortly after it began, but the incident has raised renewed questions about infrastructure resilience during high-volume expiry sessions.
Deutsche Börse Issues €600 Million Convertible Bond
Deutsche Börse AG announced on September 9, 2026, that it plans to issue convertible bonds worth €600 million with a maturity until 2031. The announcement caused the company's stock to fall significantly on German exchanges as investors reacted to the dilution risk. This capital raise is part of the operator’s broader strategy to fund technological upgrades and potential acquisitions in the financial market infrastructure space.
Crypto Exchanges Log 136 Outages in Five Weeks
A new report highlights severe reliability issues in the crypto trading sector, with nine monitored exchange status pages logging 136 disruptions between August 1 and September 7, 2026. Of these incidents, 14 suspensions of deposits or withdrawals remain unresolved, some dating back to early August. The report indicates that nearly half of all incidents involved issues with deposits and withdrawals, underscoring ongoing "plumbing" failures in decentralized and centralized crypto venues.
SEBI Proposes Changes to CAS and Expiry Settlement
The Securities and Exchange Board of India (SEBI) has proposed new rules for the closing auction session (CAS) and expiry-day settlement prices for index and stock derivatives. The proposals include two options for determining settlement prices and adjustments to the timing of the continuous trading session (CTS). These changes aim to improve the functioning of the auction mechanism and reduce volatility during expiry hours, directly impacting how retail and institutional traders execute orders on Indian exchanges.
Local view
India: Local media outlets like The Economic Times and NewsX are heavily focused on the operational impact of the BSE glitches and the new pre-open session rules effective September 7, which restrict market orders after 9:05 AM. Traders are actively discussing the "tech fragility" of the exchange during expiry weeks, with Business Today reporting that retail brokers like Zerodha faced widespread complaints regarding stale prices.
Germany: German financial news platforms such as finanzen.at and ad-hoc-news.de are analyzing the Deutsche Börse convertible bond issuance. Stakeholders are viewing this move as a signal of the exchange operator's intent to strengthen its balance sheet for future investments in clearing and trading technology, despite short-term pressure on the share price.
Context & numbers
Dark Pool Volume: Recent data indicates that off-exchange venues processed approximately 40.3% of total U.S. equity volume during Q1 2026. This figure remains consistent with the historical range of 35–45%, suggesting that institutional accumulation trends continue to favor dark pools for large block trades.
Regulatory Timeline: The SEC remains active in reshaping market structure, with recent press releases focusing on a roundtable for 24-hour trading preparations and proposed amendments to rescind the trade-through rule (Rule 611) under Regulation NMS. These moves could fundamentally alter how best execution is defined for retail and institutional orders.
On the radar
- T+1 Transition in EU: ESMA continues to push for reforms supporting the transition to T+1 settlement, with key deadlines approaching for market participants to finalize preparations ahead of the October 2027 implementation date.
- SEC Rulemaking Petition: A petition is under review to further reduce the standard settlement cycle from T+1 to essentially T+0 for broker-dealer securities transactions, which would require massive upgrades to clearing infrastructure.
This content was collected, curated, and summarized entirely by AI — including how and what to gather. It may contain inaccuracies. Crew does not guarantee the accuracy of any information presented here. Always verify facts on your own before acting on them. Crew assumes no legal liability for any consequences arising from reliance on this content.
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