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 | |
|---|---|---|---|---|---|---|
3426
Robert Half
RHI
$4.04B
| $438K | ﹤0.01% |
16,144
-4,667
| -22% | -$133K |
|
3427
PUT
MoonLake Immunotherapeutics
MLTX
$1.61B
| $436K | ﹤0.01% |
33,100
-172,400
| -84% | -$2.03M |
|
3428
PUT
National Health Investors
NHI
$3.85B
| $435K | ﹤0.01% |
5,700
+4,400
| +338% | +$337K |
|
3429
CALL
Bio-Techne
TECH
$11.2B
| $435K | ﹤0.01% |
7,400
-1,400
| -16% | -$85.1K |
|
3430
CALL
Rezolute
RZLT
$464M
| $435K | ﹤0.01% |
184,400
+143,700
| +353% | +$1.13M |
|
3431
PUT
Evergy
EVRG
$19.9B
| $435K | ﹤0.01% |
6,000
+5,600
| +1,400% | +$425K |
|
3432
Freshworks
FRSH
$3.1B
| $434K | ﹤0.01% |
35,457
-27,115
| -43% | -$320K |
|
3433
Amdocs
DOX
$5.84B
| $434K | ﹤0.01% |
5,394
+2,573
| +91% | +$207K |
|
3434
CALL
NB Bancorp
NBBK
$1.01B
| $434K | ﹤0.01% |
21,900
+13,400
| +158% | +$255K |
|
3435
CALL
Eagle Materials
EXP
$6.81B
| $434K | ﹤0.01% |
2,100
+400
| +24% | +$88.3K |
|
3436
CALL
Inspire Medical Systems
INSP
$1.5B
| $433K | ﹤0.01% |
4,700
+1,800
| +62% | +$172K |
|
3437
CALL
Leidos
LDOS
$15B
| $433K | ﹤0.01% |
2,400
-23,600
| -91% | -$4.47M |
|
3438
CALL
Toro Company
TTC
$9.08B
| $433K | ﹤0.01% |
5,500
+5,000
| +1,000% | +$370K |
|
3439
Direxion Daily TSLA Bull 2X ETF
TSLL
$2.39B
| $433K | ﹤0.01% |
22,636
-411,060
| -95% | -$8.17M |
|
3440
PUT
Global E Online
GLBE
$6.53B
| $432K | ﹤0.01% |
11,000
+100
| +0.9% | +$3.71K |
|
3441
CALL
Cemex
CX
$17.3B
| $432K | ﹤0.01% |
37,600
-69,200
| -65% | -$716K |
|
|
IVES
3442
Dan IVES Wedbush AI Revolution ETF
IVES
$961M
| $432K | ﹤0.01% |
13,662
-21,742
| -61% | -$712K |
|
|
ARIS
3443
PUT
Aris Mining
ARIS
$2.97B
| $432K | ﹤0.01% |
+26,600
| New | +$327K |
|
3444
PUT
Fortuna Silver Mines
FSM
$2.54B
| $432K | ﹤0.01% |
44,000
-26,400
| -38% | -$238K |
|
3445
PUT
PepGen
PEPG
$125M
| $432K | ﹤0.01% |
66,300
+23,700
| +56% | +$123K |
|
3446
AptarGroup
ATR
$8.75B
| $431K | ﹤0.01% |
3,534
+1,600
| +83% | +$198K |
|
3447
PUT
Trinity Capital Inc.
TRIN
$1.59B
| $431K | ﹤0.01% |
29,400
+28,100
| +2,162% | +$419K |
|
3448
Stride
LRN
$4.03B
| $430K | ﹤0.01% |
+6,625
| New | +$602K |
|
3449
Fresenius Medical Care
FMS
$13.3B
| $430K | ﹤0.01% |
+18,038
| New | +$449K |
|
3450
Timken Company
TKR
$9.64B
| $429K | ﹤0.01% |
5,102
+5,022
| +6,278% | +$399K |
|
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.