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 | |
|---|---|---|---|---|---|---|
4576
CALL
Alkami Technology
ALKT
$1.96B
| $145K | ﹤0.01% |
6,300
+500
| +9% | +$11K |
|
4577
CALL
Simpson Manufacturing
SSD
$7.79B
| $145K | ﹤0.01% |
900
+800
| +800% | +$135K |
|
4578
Buckle
BKE
$2.32B
| $145K | ﹤0.01% |
2,708
+1,227
| +83% | +$68.4K |
|
4579
1-800-Flowers.com
FLWS
$252M
| $145K | ﹤0.01% |
+36,782
| New | +$144K |
|
|
ELME
4580
PUT
Elme Communities
ELME
$145M
| $144K | ﹤0.01% |
+8,300
| New | +$141K |
|
4581
CALL
Moelis & Co
MC
$4.85B
| $144K | ﹤0.01% |
2,100
-100
| -5% | -$6.67K |
|
4582
PUT
Seres Therapeutics
MCRB
$45M
| $144K | ﹤0.01% |
9,700
-1,800
| -16% | -$31.4K |
|
4583
PUT
Treace Medical Concepts
TMCI
$262M
| $144K | ﹤0.01% |
+58,900
| New | +$256K |
|
4584
PUT
IMAX
IMAX
$2.67B
| $144K | ﹤0.01% |
3,900
-1,400
| -26% | -$48.8K |
|
4585
PUT
GSI Technology
GSIT
$201M
| $144K | ﹤0.01% |
23,200
+21,500
| +1,265% | +$153K |
|
4586
Ranpak Holdings
PACK
$500M
| $144K | ﹤0.01% |
26,615
+15,571
| +141% | +$81.9K |
|
4587
Pentair
PNR
$10.6B
| $144K | ﹤0.01% |
1,381
-10,363
| -88% | -$1.11M |
|
4588
PUT
SK Telecom
SKM
$11.4B
| $144K | ﹤0.01% |
7,000
+5,000
| +250% | +$103K |
|
4589
Aecom
ACM
$9.46B
| $144K | ﹤0.01% |
+1,507
| New | +$177K |
|
4590
CALL
InflaRx
IFRX
$243M
| $144K | ﹤0.01% |
142,100
+32,100
| +29% | +$39.9K |
|
4591
iShares MSCI ACWI ETF
ACWI
$32B
| $143K | ﹤0.01% |
1,014
-314
| -24% | -$44.1K |
|
|
MFA
4592
CALL
MFA Financial
MFA
$932M
| $143K | ﹤0.01% |
15,400
+7,300
| +90% | +$68K |
|
4593
PUT
Camden Property Trust
CPT
$11.5B
| $143K | ﹤0.01% |
1,300
-500
| -28% | -$52K |
|
|
LAZR
4594
CALL
DELISTED
Luminar Technologies
LAZR
| $143K | ﹤0.01% |
1,787,800
+392,400
| +28% | +$514K |
|
4595
CALL
Gaming and Leisure Properties
GLPI
$13B
| $143K | ﹤0.01% |
3,200
-900
| -22% | -$39.9K |
|
4596
Hess Midstream
HESM
$5.19B
| $143K | ﹤0.01% |
4,139
+1,469
| +55% | +$49.4K |
|
4597
PUT
First Bancorp
FNLC
$401M
| $143K | ﹤0.01% |
+5,400
| New | +$139K |
|
4598
Microbot Medical
MBOT
$112M
| $142K | ﹤0.01% |
71,227
+51,138
| +255% | +$121K |
|
4599
Similarweb
SMWB
$627M
| $142K | ﹤0.01% |
18,997
-66,225
| -78% | -$534K |
|
4600
PUT
Scholastic
SCHL
$774M
| $142K | ﹤0.01% |
4,800
+1,600
| +50% | +$45.9K |
|
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.