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 | |
|---|---|---|---|---|---|---|
5501
CALL
WEX
WEX
$6.37B
| $59.6K | ﹤0.01% |
+400
| New | +$60.3K |
|
5502
St. Joe Company
JOE
$3.54B
| $59.5K | ﹤0.01% |
1,002
-6,690
| -87% | -$375K |
|
5503
Neuronetics
STIM
$138M
| $59.5K | ﹤0.01% |
43,085
-101,405
| -70% | -$212K |
|
5504
Global X Data Center & Digital Infrastructure ETF
DTCR
$2.1B
| $59.4K | ﹤0.01% |
2,817
-43
| -2% | -$916 |
|
5505
Ryder
R
$9.83B
| $59.3K | ﹤0.01% |
310
-5,672
| -95% | -$1.02M |
|
|
SEG
5506
PUT
Seaport Entertainment Group
SEG
$336M
| $59.3K | ﹤0.01% |
3,000
+2,800
| +1,400% | +$62.8K |
|
5507
PUT
Driven Brands
DRVN
$2.35B
| $59.3K | ﹤0.01% |
4,000
-2,700
| -40% | -$40.2K |
|
|
SJT
5508
San Juan Basin Royalty Trust
SJT
$117M
| $59.2K | ﹤0.01% |
10,532
+2,855
| +37% | +$16.5K |
|
5509
CALL
Ibotta
IBTA
$559M
| $59.1K | ﹤0.01% |
2,600
+1,900
| +271% | +$51.3K |
|
5510
PUT
Cavco Industries
CVCO
$4.22B
| $59.1K | ﹤0.01% |
100
| – | – |
|
5511
CALL
Brookfield Infrastructure Partners
BIP
$19.2B
| $59.1K | ﹤0.01% |
1,700
-5,100
| -75% | -$178K |
|
5512
Polestar Automotive Holding UK
PSNY
$2.09B
| $59K | ﹤0.01% |
2,763
+1,545
| +127% | +$32.2K |
|
5513
Vanguard Morningstar Large-Cap ETF
VV
$52.4B
| $58.9K | ﹤0.01% |
+187
| New | +$58.4K |
|
|
ANGX
5514
PUT
Angel Studios
ANGX
$757M
| $58.8K | ﹤0.01% |
+12,600
| New | +$74.7K |
|
5515
PUT
Beazer Homes USA
BZH
$877M
| $58.8K | ﹤0.01% |
2,900
-1,900
| -40% | -$42.3K |
|
5516
CALL
Horizon Technology Finance
HRZN
$295M
| $58.7K | ﹤0.01% |
9,100
-1,100
| -11% | -$7.03K |
|
|
ODVWW
5517
PUT
DELISTED
Osisko Development Corp. Warrant
ODVWW
| $58.6K | ﹤0.01% |
16,800
+15,200
| +950% | +$53K |
|
|
ALMS
5518
PUT
Alumis Inc
ALMS
$3.6B
| $58.6K | ﹤0.01% |
6,000
-286,500
| -98% | -$2M |
|
5519
C4 Therapeutics
CCCC
$385M
| $58.6K | ﹤0.01% |
30,658
+22,822
| +291% | +$54.1K |
|
|
KRMN
5520
CALL
Karman Holdings
KRMN
$6.38B
| $58.5K | ﹤0.01% |
800
-3,800
| -83% | -$275K |
|
5521
CALL
MGIC Investment
MTG
$6.16B
| $58.4K | ﹤0.01% |
+2,000
| New | +$56.2K |
|
|
ADAM
5522
CALL
Adamas Trust
ADAM
$815M
| $58.4K | ﹤0.01% |
8,000
-13,200
| -62% | -$93.7K |
|
|
CMBM
5523
CALL
DELISTED
Cambium Networks
CMBM
| $58.3K | ﹤0.01% |
+40,500
| New | +$68.8K |
|
|
PLTU
5524
Direxion Daily PLTR Bull 2X ETF
PLTU
$376M
| $58.3K | ﹤0.01% |
+793
| New | +$73K |
|
5525
PUT
International Seaways
INSW
$4.76B
| $58.3K | ﹤0.01% |
1,200
-700
| -37% | -$34.6K |
|
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.