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 | |
|---|---|---|---|---|---|---|
4701
Nano X Imaging
NNOX
$61.1M
| $130K | ﹤0.01% |
46,545
-55,675
| -54% | -$200K |
|
4702
Atkore
ATKR
$2.41B
| $130K | ﹤0.01% |
+2,060
| New | +$134K |
|
|
KC
4703
PUT
Kingsoft Cloud Holdings
KC
$2.96B
| $130K | ﹤0.01% |
12,600
-115,900
| -90% | -$1.42M |
|
4704
iShares US Healthcare Providers ETF
IHF
$1.22B
| $130K | ﹤0.01% |
2,712
+2,414
| +810% | +$118K |
|
4705
PUT
Oxford Industries
OXM
$581M
| $130K | ﹤0.01% |
3,800
-15,300
| -80% | -$569K |
|
4706
CALL
Matthews China Innovators Active ETF
MCHS
$20M
| $130K | ﹤0.01% |
+4,000
| New | +$134K |
|
4707
CALL
Global Partners
GLP
$1.65B
| $130K | ﹤0.01% |
3,100
+3,000
| +3,000% | +$132K |
|
4708
Mohawk Industries
MHK
$6.91B
| $129K | ﹤0.01% |
1,184
+634
| +115% | +$72.8K |
|
4709
Lexeo Therapeutics
LXEO
$338M
| $129K | ﹤0.01% |
13,031
+12,532
| +2,511% | +$114K |
|
4710
PUT
MINISO
MNSO
$3.88B
| $129K | ﹤0.01% |
6,900
-8,800
| -56% | -$183K |
|
4711
CALL
PTC Therapeutics
PTCT
$6.18B
| $129K | ﹤0.01% |
1,700
-2,800
| -62% | -$203K |
|
4712
Adtran
ADTN
$675M
| $129K | ﹤0.01% |
14,847
-2,593
| -15% | -$22.5K |
|
4713
PUT
Warner Music
WMG
$15.2B
| $129K | ﹤0.01% |
4,200
+1,900
| +83% | +$58K |
|
4714
Matthews International
MATW
$887M
| $129K | ﹤0.01% |
4,930
-2,918
| -37% | -$71.7K |
|
4715
CALL
InfraCap MLP ETF
AMZA
$466M
| $129K | ﹤0.01% |
5,800
+2,400
| +71% | +$94.7K |
|
4716
Newell Brands
NWL
$2.21B
| $129K | ﹤0.01% |
+34,545
| New | +$140K |
|
|
MRP
4717
CALL
Millrose Properties Inc
MRP
$4.66B
| $128K | ﹤0.01% |
4,300
-15,000
| -78% | -$470K |
|
|
WULX
4718
Tradr 2X Long WULF Daily ETF
WULX
$11.6M
| $128K | ﹤0.01% |
+7,861
| New | +$200K |
|
4719
CALL
Fidelity Nasdaq Composite Index ETF
ONEQ
$9.97B
| $128K | ﹤0.01% |
1,400
+400
| +40% | +$36.4K |
|
4720
Alector
ALEC
$169M
| $128K | ﹤0.01% |
82,017
-18,927
| -19% | -$33.6K |
|
|
ATYR
4721
CALL
aTyr Pharma
ATYR
$47.4M
| $128K | ﹤0.01% |
163,300
-244,500
| -60% | -$201K |
|
4722
CALL
AvePoint
AVPT
$2.76B
| $128K | ﹤0.01% |
9,200
-98,800
| -91% | -$1.36M |
|
4723
PUT
Caleres
CAL
$432M
| $128K | ﹤0.01% |
10,500
+8,300
| +377% | +$102K |
|
4724
PUT
Repay Holdings
RPAY
$335M
| $128K | ﹤0.01% |
35,000
-12,300
| -26% | -$49.3K |
|
4725
CALL
Byrna Technologies
BYRN
$98.3M
| $128K | ﹤0.01% |
7,600
-36,400
| -83% | -$709K |
|
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.