Simplex Trading Portfolio holdings
Simplex Trading, founded in 2004 and headquartered in Chicago, Illinois, is a technology-driven proprietary trading firm specializing in market-making and liquidity provision, primarily in U.S. equity options and futures options. Leveraging advanced proprietary software and data-driven analysis, the firm optimizes trading strategies and develops innovative solutions to capitalize on financial market opportunities, maintaining a competitive edge through automation and a collaborative team of technologists and traders. With a workforce exceeding 300 and led by CEO Erik Swanson since 2014, Simplex operates with a low-ego, high-intelligence culture, focusing on minimal bureaucracy and rapid execution, while also making strategic venture capital investments in fintech startups. Recognized as a top workplace in Chicago by Built In’s 2025 awards, Simplex continues to evolve, blending cutting-edge technology with a commitment to market efficiency and growth.
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
Netflix
NFLX
|
+$73.1M |
| 2 |
Western Digital
WDC
|
+$51.8M |
| 3 |
iShares Semiconductor ETF
SOXX
|
+$46M |
| 4 |
Meta Platforms (Facebook)
META
|
+$41.8M |
| 5 |
Alibaba
BABA
|
+$37.1M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
NVIDIA
NVDA
|
+$262M |
| 2 |
Microsoft
MSFT
|
+$194M |
| 3 |
iShares Russell 2000 ETF
IWM
|
+$149M |
| 4 |
Apple
AAPL
|
+$119M |
| 5 |
Amazon
AMZN
|
+$107M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 0.59% |
| 2 | Consumer Discretionary | 0.21% |
| 3 | Healthcare | 0.2% |
| 4 | Industrials | 0.18% |
| 5 | Communication Services | 0.16% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
6776
CALL
Fidelity Corporate Bond ETF
FCOR
$351M
| $13.8K | ﹤0.01% |
300
-100
| -25% | -$4.81K |
|
6777
CALL
Fortrea Holdings
FTRE
$1.82B
| $13.8K | ﹤0.01% |
800
-40,200
| -98% | -$497K |
|
6778
Direxion Daily Transportation Bull 3X ETF
TPOR
$17.6M
| $13.8K | ﹤0.01% |
+459
| New | +$13K |
|
|
CEPI
6779
REX Crypto Equity Premium Income ETF
CEPI
$108M
| $13.7K | ﹤0.01% |
408
+244
| +149% | +$9.29K |
|
6780
CALL
Quaker Houghton
KWR
$2.79B
| $13.7K | ﹤0.01% |
100
-1,400
| -93% | -$189K |
|
6781
Werner Enterprises
WERN
$2.24B
| $13.7K | ﹤0.01% |
456
+441
| +2,940% | +$12.1K |
|
6782
Aspen Aerogels
ASPN
$384M
| $13.7K | ﹤0.01% |
4,832
-11,419
| -70% | -$58.9K |
|
6783
iShares MSCI USA Value Factor ETF
VLUE
$9.17B
| $13.7K | ﹤0.01% |
+100
| New | +$13.1K |
|
6784
CALL
SoundThinking
SSTI
$100M
| $13.7K | ﹤0.01% |
1,700
-14,300
| -89% | -$125K |
|
6785
PUT
Omnicell
OMCL
$1.61B
| $13.6K | ﹤0.01% |
300
+100
| +50% | +$3.66K |
|
6786
PUT
Grid Dynamics Holdings
GDYN
$576M
| $13.5K | ﹤0.01% |
1,500
+1,300
| +650% | +$11.3K |
|
6787
BARK
BARK
$81.8M
| $13.5K | ﹤0.01% |
1,122
-1,635
| -59% | -$24.3K |
|
6788
PUT
WPP
WPP
$4.36B
| $13.5K | ﹤0.01% |
600
-3,400
| -85% | -$73.1K |
|
6789
PUT
Xenon Pharmaceuticals
XENE
$6.06B
| $13.4K | ﹤0.01% |
300
+100
| +50% | +$4.2K |
|
|
DIPS
6790
YieldMax Short NVDA Option Income Strategy ETF
DIPS
$7.83M
| $13.4K | ﹤0.01% |
262
+239
| +1,039% | +$13.1K |
|
6791
abrdn Bloomberg All Commodity Longer Dated Strategy K-1 Free ETF
BCD
$402M
| $13.4K | ﹤0.01% |
+434
| New | +$15.3K |
|
6792
Carlisle Companies
CSL
$14.6B
| $13.4K | ﹤0.01% |
+42
| New | +$13.6K |
|
6793
CALL
Medallion Financial
MFIN
$229M
| $13.4K | ﹤0.01% |
1,300
-5,000
| -79% | -$50.1K |
|
6794
Bar Harbor Bankshares
BHB
$665M
| $13.4K | ﹤0.01% |
430
+296
| +221% | +$9.01K |
|
6795
CALL
Expro Ltd
XPRO
$1.79B
| $13.3K | ﹤0.01% |
1,000
-18,000
| -95% | -$243K |
|
6796
CALL
HUTCHMED
HCM
$1.93B
| $13.3K | ﹤0.01% |
+1,000
| New | +$14.6K |
|
6797
CALL
EverCommerce
EVCM
$2.18B
| $13.3K | ﹤0.01% |
+1,100
| New | +$11.7K |
|
6798
CALL
Phunware
PHUN
$43.1M
| $13.3K | ﹤0.01% |
7,200
-14,200
| -66% | -$33K |
|
6799
iShares US Energy ETF
IYE
$1.74B
| $13.3K | ﹤0.01% |
280
+80
| +40% | +$3.79K |
|
6800
CALL
Qualys
QLYS
$5.1B
| $13.3K | ﹤0.01% |
100
-500
| -83% | -$68.8K |
|
Similar funds
Simplex Trading's Q4 2025 Portfolio in Review
As of Q4 2025, Simplex Trading held 10,526 positions worth $177B, down 9% from $195B the previous quarter. Its ten largest holdings account for 49% of the portfolio.
Simplex Trading withdrew a net $23.2B in Q4 2025, closing 2,184 positions and reducing 4,088 holdings. Its most notable exit was iShares Russell 2000 ETF, an estimated $149M position sold in full.
By sector, the portfolio is most concentrated in Technology at 0.59% of assets, down from 0.79% a quarter earlier, followed by Consumer Discretionary and Healthcare.
Against the trend, Simplex Trading opened a new position in Western Digital worth $58.9M.
- Simplex Trading's largest Q4 2025 buy was Western Digital: 341,762 shares worth $58.9M.
- Simplex Trading added most to Netflix in Q4 2025, an estimated $73.1M increase.
- Simplex Trading's biggest Q4 2025 reduction was NVIDIA, cutting an estimated $262M.
- Simplex Trading fully exited iShares Russell 2000 ETF in Q4 2025, selling an estimated $149M.
- Simplex Trading's ten largest holdings make up 49% of its $177B portfolio in Q4 2025.
- Simplex Trading opened 1,476 new positions and closed 2,184 in Q4 2025.
- Simplex Trading's portfolio value fell 9% quarter-over-quarter to $177B.
Based on Simplex Trading's 13F filing for Q4 2025, filed 11 Feb 2026.