State of Overnight ATS Markets
Q1 2026
An institutional analysis of overnight Alternative Trading System activity combining FINRA Rule 4552 weekly transparency data (Jan 26 – Mar 16, 2026), SEC EDGAR ATS-N operational filings, and 88,016 proprietary BlueOcean session records spanning 109 trading days.
01 / Executive Summary
BlueOcean ATS processed $311.5 billion in notional across 88,016 overnight session trades between September 2, 2025 and April 9, 2026. That figure covers 109 trading days and 3,751 unique symbols, with average daily notional of $2.86 billion per session. Monthly notional grew from $28.6 billion in September 2025 to $85.6 billion in March 2026 -- a 3x increase in six months that reflects accelerating institutional adoption of the overnight session as a primary execution venue.
FINRA Rule 4552 weekly data for the eight weeks ending March 16, 2026 reveals the ATS competitive landscape across 16 monitored venues. Within that universe, MS Trajectory Cross (MSTX) leads by share volume at 5.36 billion shares, followed by UBS ATS (4.91 billion) and Level ATS (3.46 billion). The full FINRA ATS reporting universe -- which includes venues outside this monitored set -- shows Intelligent Cross leading by market share at 16.6% of reported NMS ATS weekly volume, per Sapinover's live venue-intelligence tracking.
Three venues operate exclusively in the overnight window: BlueOcean ATS (BOATS), Bruce Markets (BOSS), and Moon ATS (MOON). Each has filed distinct operational architecture with the SEC under Form ATS-N. CODA Markets filed a cessation notice (ATS-N-C) in March 2026, consolidating overnight order flow into the three remaining venues.
02 / Data Snapshot
BlueOcean Session Analytics — Sep 2, 2025 through Apr 9, 2026
FINRA Rule 4552 Weekly Data — 8 Weeks: Jan 26 through Mar 16, 2026 (16 monitored MPIDs)
03 / BlueOcean Monthly Notional Trend
Monthly notional on BlueOcean ATS from the Sapinover session analytics pipeline. October 2025 is absent from the dataset (no BOATS files received). November 2025 has one recorded trading day, indicating a data gap in the collection pipeline for that month. All other months reflect complete session coverage.
| Month | Total Notional | Trading Days | Avg Daily |
|---|---|---|---|
| Sep 2025 | $28.6B | 20 | $1.43B |
| Oct 2025 | -- (no data) | -- | -- |
| Nov 2025 | $4.1B | 1 (gap) | -- |
| Dec 2025 | $46.1B | 22 | $2.09B |
| Jan 2026 | $62.8B | 20 | $3.14B |
| Feb 2026 | $57.4B | 18 | $3.19B |
| Mar 2026 | $85.6B | 22 | $3.89B |
| Apr 2026 (partial) | $26.9B | 6 | $4.48B |
Source: Sapinover BlueOcean session analytics pipeline. Notional = sum of session-level notional for all symbols meeting $50K minimum filter. Oct/Nov gap reflects collection pipeline issue, not venue downtime.
Growth Signal
Average daily notional increased from $1.43B in September 2025 to $3.89B in March 2026, and the partial April 2026 read ($4.48B/day over 6 sessions) suggests the trend continued into Q2. This is not seasonal noise -- January through April show sequential month-over-month expansion even accounting for day-count differences.
04 / FINRA Volume Rankings: Monitored ATS Universe
FINRA Rule 4552 weekly statistics for 16 ATSs in the Sapinover-monitored universe, covering 8 weeks from January 26 through March 16, 2026. Rankings are by total share volume across all 8 weeks. This table reflects the CalcGuard-affiliated MPID set and does not represent the full FINRA ATS reporting universe.
For full-universe share rankings (including venues outside this monitored set), see the Venue Volume Intelligence page.
| Rank | ATS Name | MPID | Total Shares (8 wk) | Total Notional (8 wk) | Avg Trade Size |
|---|---|---|---|---|---|
| 1 | MS Trajectory Cross (ATS-1) | MSTX | 5.36B | $326.2B | ~3,994 sh |
| 2 | UBS ATS | UBSA | 4.91B | $299.3B | ~3,989 sh |
| 3 | Level ATS | EBXL | 3.46B | $180.7B | ~2,846 sh |
| 4 | PureStream | PURE | 3.29B | $247.3B | ~2,318 sh |
| 5 | BIDS ATS | BIDS | 3.21B | $178.3B | ~41,087 sh |
| 6 | MS Pool (ATS-4) | MSPL | 2.90B | $146.1B | ~12,729 sh |
| 7 | Sigma X2 | SGMT | 2.87B | $184.7B | ~3,837 sh |
| 8 | JPB-X | JPBX | 2.04B | $143.1B | ~5,299 sh |
| 9 | IBKR ATS | IATS | 1.64B | $71.8B | ~12,718 sh |
| 10 | JPM-X | JPMX | 1.37B | $75.3B | ~6,318 sh |
| 11 | CrossStream | XSTM | 1.23B | $42.9B | ~27,315 sh |
| 12 | The Barclays ATS | LATS | 1.07B | $57.9B | ~7,298 sh |
| 13 | Liquidnet H2O ATS | LQNA | 599M | $43.0B | ~44,573 sh |
| 14 | MS RPool (ATS-6) | MSRP | 346M | $24.4B | ~4,620 sh |
| 15 | Liquidnet Negotiation ATS | LQNT | 161M | $11.7B | ~164,655 sh |
| 16 | CODA / CODA Markets | CODA | 136M | $5.9B | ~10,780 sh |
Source: FINRA Rule 4552 weekly ATS data, Sapinover analytics pipeline. 8 weeks ending Mar 16, 2026. Avg trade size = total shares / total trades. CODA ceased operations Mar 20, 2026 (ATS-N-C cessation filing).
Universe Scope Note
This table covers 16 ATSs in the Sapinover-monitored FINRA dataset. The full FINRA ATS reporting universe includes additional venues not in this set. Live full-universe share rankings -- sourced directly from FINRA's weekly transparency data -- are available on the Venue Volume Intelligence page and show Intelligent Cross leading with 16.6% of total reported NMS ATS weekly volume.
05 / BlueOcean Top 15 Symbols by Overnight Notional
Cumulative notional by symbol across all BlueOcean overnight sessions from September 2, 2025 through April 9, 2026. The presence of SLV, GLD, and AGQ (silver and gold ETFs) in the top 15 alongside semiconductor and tech names reflects the macro-driven, commodity-sensitive nature of overnight institutional positioning.
| Rank | Symbol | Total Notional (Sep 25 - Apr 26) | Category |
|---|---|---|---|
| 1 | TSLA | $20.7B | Single name / EV |
| 2 | SLV | $15.2B | ETF / Silver |
| 3 | NVDA | $14.6B | Single name / Semiconductors |
| 4 | QQQ | $13.7B | ETF / Nasdaq 100 |
| 5 | MU | $12.4B | Single name / Memory |
| 6 | SOXL | $11.5B | ETF / 3x Semiconductors (leveraged) |
| 7 | GLD | $9.2B | ETF / Gold |
| 8 | SNDK | $8.5B | Single name / Storage |
| 9 | TQQQ | $8.2B | ETF / 3x Nasdaq (leveraged) |
| 10 | SPY | $7.4B | ETF / S&P 500 |
| 11 | BABA | $7.3B | Single name / China Tech |
| 12 | AGQ | $6.7B | ETF / 2x Silver (leveraged) |
| 13 | SQQQ | $5.6B | ETF / -3x Nasdaq (inverse leveraged) |
| 14 | PLTR | $4.5B | Single name / AI/Data |
| 15 | GOOGL | $4.4B | Single name / Mega-cap Tech |
Source: Sapinover BlueOcean session analytics pipeline. Notional = sum of VWAP_Price x Volume per trade record. $50K minimum filter applied.
Asset Mix
ETFs account for 47.5% of total overnight notional, single-name stocks 52.5%. In the top 15, 7 of 15 symbols are ETFs (SLV, QQQ, SOXL, GLD, TQQQ, SPY, AGQ, SQQQ), including three leveraged products (SOXL 3x, TQQQ 3x, SQQQ -3x) and two commodity ETFs (SLV, GLD). This concentration reflects overnight use for macro-level and commodity-driven portfolio adjustments.
Sector Breakdown
06 / Overnight Venue Profiles: SEC EDGAR ATS-N Filings
All three overnight ATSs have filed operational disclosures with the SEC under Form ATS-N. CIK numbers and filing details are sourced directly from SEC EDGAR. CODA Markets ceased operations March 20, 2026 via ATS-N-C cessation filing.
BlueOcean ATS
Blue Ocean ATS, LLC
Bruce Markets
Bruce Markets LLC
Moon ATS
Moon ATS LLC
Shared Infrastructure
All three overnight venues are co-located at Equinix NY4 in Secaucus, New Jersey -- the same data center that houses NYSE, Nasdaq, CBOE, and the major institutional dark pools. Physical co-location is documented in each venue's Form ATS-N filing. The convergence on a single facility means latency between overnight and regular-session venues is sub-millisecond, enabling institutional participants to manage overnight and day-session positions within a unified infrastructure footprint.
BlueOcean OFA Disclosure Cycle
BlueOcean has filed 52 ATS-N documents (initial filing plus monthly Order Flow Attribution amendments) as of the report date. Monthly OFA filings are a voluntary disclosure above the regulatory minimum, detailing counterparty composition across broker-dealer, institutional investor, and market maker categories. This disclosure cadence is the highest among the three overnight venues and provides compliance teams with quarterly-lagged counterparty data for best execution analysis.
07 / Session Analytics: Timing Differential and Directional Consistency
Sapinover's core analytical metric is Timing Differential: the spread between a symbol's BlueOcean overnight VWAP and the subsequent regular-session open, normalized to the prior close, expressed in basis points. Directional Consistency measures whether the overnight VWAP was positioned favorably relative to the direction of the next-day open gap.
Interpretation Note
A negative mean timing differential indicates that, on average, the overnight VWAP was above the subsequent regular-session open -- meaning execution in the overnight session was at a higher price than what the next morning's market offered. The median of -19.0 bps is a better representation of the typical session than the mean of -66.1 bps, which is skewed by outlier sessions (the 3.5% outlier rate represents 3,039 records outside the 5th/95th percentile bounds).
Directional Consistency at 70.1% means that in 70% of cases where a next-day open gap was positive, the overnight VWAP was positioned below the open (favorable for long holders), and vice versa for negative gaps. This metric is the central construct for evaluating overnight execution quality relative to next-day market conditions. Full distribution analysis is available on the Market Intelligence dashboard.
08 / Regulatory Developments: Q1 2026
CODA Markets filed an ATS-N-C cessation notice with the SEC effective March 20, 2026. The filing is publicly available on SEC EDGAR. CODA operated as an institutional crossing venue and its exit consolidates overnight order flow into the three remaining active venues. This is a verified SEC filing event, not an estimate.
BlueOcean has maintained a monthly Order Flow Attribution amendment cycle, accumulating 52 total ATS-N filings on SEC EDGAR (CIK 0001795131). The count is sourced from EDGAR directly. Monthly OFA amendments are a voluntary transparency commitment above the regulatory minimum under Regulation ATS-N.
tZERO ATS ceased equity operations in May 2021, per its ATS-N-C filing on EDGAR. Its filing history provides regulatory precedent for overnight ATS cessation events and documents the disclosure requirements under Rule 301(b)(2) of Regulation ATS.
09 / Methodology and Data Sources
BlueOcean Session Data
Proprietary session data sourced directly from BlueOcean ATS daily market statistics reports, delivered via email attachment. Processed through the Sapinover analytics pipeline: yfinance enrichment for prior close, next open, and next close; $50,000 notional minimum institutional filter applied; Timing Differential and Reference Gap calculated in basis points. Dataset: 88,016 records, 109 trading days, Sep 2, 2025 through Apr 9, 2026.
FINRA Rule 4552 Data
FINRA ATS weekly statistics accessed via the FINRA Developer API (OAuth2 client credentials). Data covers NMS Tier 1 (S&P 500 / Russell 1000) and Tier 2 (remaining NMS stocks). The Sapinover pipeline tracks 16 ATSs (a subset of CalcGuard-affiliated MPIDs) across 8 weeks: January 26 through March 16, 2026. Approximately a two-week publication lag applies. Full-universe rankings are sourced from the live Sapinover venue-intelligence feed.
SEC EDGAR
Form ATS-N filings, amendments (ATS-N/UA, ATS-N/MA, ATS-N/OFA), and cessation notices (ATS-N-C) retrieved via SEC EDGAR full-text search and company filing endpoints. CIK numbers verified against EDGAR company records. Filing counts reflect the EDGAR database as of report publication date.
Compliance Disclosure
This report is produced by Sapinover LLC for informational purposes only. It does not constitute investment advice, a recommendation to buy or sell any security, or a solicitation of any investment product. All statistics are sourced from the data systems described above. No figures are estimated or extrapolated except where explicitly noted. Enrico Cacciatore is FINRA licensed (Series 7, 24, 63, 55).
Access Sapinover's full overnight ATS analytics platform for live session data, timing differential analysis, and institutional flow metrics.