SRO Monitor Digest

MEMX is amending its market-wide circuit breaker rule so that after a Level 3 (20% S&P 500 decline) halt, trading resumes at 4 a.m. the next day rather than at 9 p.m. the same evening — which is what the existing rule text would imply once MEMX launches its 23/5 overnight session on December 6, 2026. The filing took effect immediately as a 'non-controversial' rule change (operative after 30 days), so the SEC did not have to approve it; the SEC retains a 60-day window to suspend it but that is unlikely given all SROs and FINRA jointly agreed to this harmonized approach. Practically, nothing changes for traders today: the post-Level-3 cooling-off period and 4 a.m. reopen are preserved even as overnight trading arrives.

Texas Stock Exchange wants to replace broker discretionary voting with a mandatory formula: any shares held by brokers for customers who didn't return voting instructions would be voted in the same proportion as the customers who did, for companies primarily listed on TXSE. This is pitched as a listing-attraction feature (easier quorum, cheaper proxy campaigns for issuers and funds) but drew strong opposition from institutional investors who say it distorts governance outcomes. The SEC's 'order instituting proceedings' is a procedural escalation, not a rejection — it pauses approval, signals the SEC has real legal concerns (notably whether the scheme conflicts with Exchange Act Section 6(b)(10)'s ban on broker voting without instructions), and opens another comment/rebuttal round; the proposal can still be approved, but the odds have meaningfully worsened and nothing changes for brokers or issuers in the meantime.

Texas Stock Exchange is setting up a Lead Market Maker program for ETPs it lists, copying Cboe BZX's long-standing framework: designated market makers commit to quoting standards in exchange for fee incentives, with loss of LMM status after two consecutive months of underperformance. Because the rule mirrors an existing exchange's rules, TXSE filed it as immediately effective and the SEC waived the usual 30-day delay, so it is live now — no SEC approval vote is needed, though the Commission retains a 60-day right to suspend it. The actual incentives and performance thresholds come in a separate fee filing; practically, this clears the way for TXSE to launch its ETP listing business in September with designated liquidity providers in place.