SIMPLEX TRADING, LLC
SEC Form 13F institutional filer · CIK 0001488542
13F-HR · 251 reported holdings · 2026-03-31
SEC-registered institutional investment manager.
Reported long-US-equity value
$1.85B
Top-10 concentration
57.9%
SIMPLEX TRADING, LLC — $1.85B AUM allocation strategy
SIMPLEX TRADING, LLC files SEC Form 13F and reports $1.85B of long US equity value across 251 reported holdings for 2026-03-31.
Its largest sector bet is Information Technology 29.7%, followed by Communication Services 14.0% and Consumer Discretionary 9.7%.
The top 10 holdings account for 58% of reported value — a conviction-weighted book concentrated in its best ideas. The sector and industry splits below are of the same reported value. Track quarter-over-quarter adds, trims, new positions and exits below — sourced from SEC 13F filings, public domain.
SIMPLEX TRADING, LLC — latest SEC 13F insights
Reported long-US-equity value (13F AUM)
$1.85B
total across 251 reported holdings · 2026-03-31 · excludes shorts, cash, non-US
Top-10 concentration
58% of value
higher = narrower conviction; lower = spread / hedging
Biggest adds (shares)
+$NVDA +768K sh · +$125M+$ORCL +383K sh · +$50.1M+$XLF +318K sh · +$15.5M
Biggest trims (shares)
−$AAPL −669K sh · −$183M−$CMCSA −665K sh · −$20M−$NFLX −506K sh · −$47M
Exited to nil (held last quarter, gone now)
$VRT ($24.6M last qtr)$NEE ($23.6M last qtr)$WBD ($20.4M last qtr)$COIN ($20.2M last qtr)$NEM ($19.7M last qtr)
Sector allocation (share of reported value)
each slice is a share of the reported long-US-equity value — smaller sectors and the rest of the book roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Industry allocation (share of reported value)
- Semiconductors19.0%—
- Interactive Media & Services14.0%—
- Broadline Retail8.6%—
- Application Software5.9%—
- Managed Health Care4.2%—
- Systems Software2.7%—
- Asset Management & Custody Banks2.1%—
- Communications Equipment2.0%—
- Other holdings41.4%—
the finer GICS cut of the same book — same denominator — smaller industries roll into “Other holdings”
Qtr shift = share-point change vs the prior quarter's filing — first period tracked for this filer; the column fills in with the next quarterly refresh.
Top S&P 500 holdings
9 of 9 rows · sorted by Value ↓
| Ticker | Holding | Shares | Value | Δ QoQ | Weight |
|---|---|---|---|---|---|
| $NVDA | NVIDIA Corporation | 1.51M | $263M | +768K | 14.2% |
| $AMZN | Amazon.com Inc | 765K | $159M | — | 8.6% |
| $META | Meta Platforms Inc | 230K | $132M | +167K | 7.1% |
| $GOOG | Alphabet Inc. Class C Capital Stock | 296K | $85.2M | +258K | 4.6% |
| $UNH | UnitedHealth Group Incorporated | 288K | $77.8M | +195K | 4.2% |
| $ORCL | Oracle Corporation | 515K | $75.7M | +383K | 4.1% |
| $AMD | Advanced Micro Devices Inc | 261K | $53M | +204K | 2.9% |
| $MSFT | Microsoft Corporation | 137K | $50.6M | +66.1K | 2.7% |
| $GOOGL | Alphabet Inc | 145K | $41.7M | +96.9K | 2.3% |
…and 242 more holdings in the full 13F filing (top positions only shown).
SEC Form 13F data sets · public domain · 45-day filing lag · >$100M AUM managers · as reported
← All 13F filers·← QuantOrb.pro
How to read Δ QoQ — the five insight categories, and the caveats
The categories. Analysts, quants and retail traders look past total portfolio value to isolate actionable signals. Five categories matter.
Conviction & concentration shifts
New positions vs complete exits — a brand-new stock signals high conviction; a full liquidation suggests a broken thesis or tax-loss harvesting. Aggressive sizing — look at share count, not dollars: a 20% share increase during a drawdown is strong dip-buying. Concentration — a narrowing top-5/10 means conviction; spreading capital across more names means hedging.
Sector & macro allocation rotations
Aggregating Δ QoQ moves across sectors shows where smart money is leaning in or sneaking out — rotating out of growth into defensives or energy, for example. The fund's total long equity exposure quarter-over-quarter is a proxy for overall institutional risk appetite.
Crowding & smart-money consensus
When several managers initiate or expand the same stock in the same quarter, that is institutional consensus. Contrarian reads: top pickers buying hard into a beaten-down name the market is selling.
Derivative & option overlays
Reported call/put changes indicate whether managers are adding downside hedges or leveraging upside exposure. Note: a long increase may be half of a market-neutral pair trade.
Who reads this
| Retail "cloners" | High-conviction ideas to replicate ~45 days after quarter-end. |
| Corporate IR | Which funds bought or dumped the stock, before the next call. |
| Quant / algo traders | Cross-sectional factor inputs: flow, momentum, ownership. |
Four caveats before you trade on it
- 45-day lag — holdings are quarter-end; positions may already be closed.
- Long-only — 13Fs miss shorts, pair trades and cash.
- No non-US / fixed income — the picture is US equities plus options.
- Corporate actions — splits and spinoffs distort raw share deltas.
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