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 | |
|---|---|---|---|---|---|---|
4351
ProShares Ultra Financials
UYG
$819M
| $177K | ﹤0.01% |
+1,933
| New | +$184K |
|
4352
PUT
Teekay
TK
$996M
| $177K | ﹤0.01% |
19,600
+16,400
| +513% | +$151K |
|
|
DRD
4353
CALL
DRDGold
DRD
$1.75B
| $177K | ﹤0.01% |
5,700
-10,300
| -64% | -$294K |
|
4354
CALL
SiTime
SITM
$13.8B
| $177K | ﹤0.01% |
500
-500
| -50% | -$156K |
|
4355
PUT
CBIZ
CBZ
$2.95B
| $177K | ﹤0.01% |
+3,500
| New | +$184K |
|
|
MAGN
4356
Magnera Corp
MAGN
$493M
| $176K | ﹤0.01% |
11,643
+10,241
| +730% | +$119K |
|
4357
PUT
MKS Inc
MKSI
$17.4B
| $176K | ﹤0.01% |
1,100
-5,300
| -83% | -$786K |
|
4358
PUT
Cadiz
CDZI
$251M
| $176K | ﹤0.01% |
+31,300
| New | +$168K |
|
4359
Sun Communities
SUI
$15.8B
| $175K | ﹤0.01% |
1,416
-2,377
| -63% | -$298K |
|
4360
PUT
ScottsMiracle-Gro
SMG
$4.09B
| $175K | ﹤0.01% |
3,000
-1,900
| -39% | -$107K |
|
|
MREO
4361
Mereo BioPharma
MREO
$48.9M
| $175K | ﹤0.01% |
419,477
+223,208
| +114% | +$425K |
|
4362
iShares MSCI Mexico ETF
EWW
$1.89B
| $175K | ﹤0.01% |
2,523
-1,375
| -35% | -$92.8K |
|
4363
CALL
Hippo Holdings
HIPO
$777M
| $174K | ﹤0.01% |
5,800
-9,900
| -63% | -$331K |
|
4364
PUT
American Resources Corp
AREC
$183M
| $174K | ﹤0.01% |
70,300
-46,800
| -40% | -$156K |
|
4365
CALL
Solventum
SOLV
$15.3B
| $174K | ﹤0.01% |
2,200
-12,100
| -85% | -$927K |
|
4366
Mineralys Therapeutics
MLYS
$2.32B
| $174K | ﹤0.01% |
4,802
+379
| +9% | +$15.2K |
|
4367
PUT
Dyne Therapeutics
DYN
$4.15B
| $174K | ﹤0.01% |
8,900
-1,400
| -14% | -$26.5K |
|
4368
CALL
Daktronics
DAKT
$946M
| $174K | ﹤0.01% |
8,800
+5,600
| +175% | +$107K |
|
|
IVES
4369
CALL
Dan IVES Wedbush AI Revolution ETF
IVES
$942M
| $174K | ﹤0.01% |
5,500
+4,600
| +511% | +$151K |
|
|
AGEN
4370
CALL
Agenus
AGEN
$276M
| $173K | ﹤0.01% |
55,200
+2,700
| +5% | +$10.8K |
|
4371
CALL
Atomera
ATOM
$173M
| $173K | ﹤0.01% |
78,300
+9,900
| +14% | +$29.9K |
|
4372
CALL
AdvanSix
ASIX
$542M
| $173K | ﹤0.01% |
+10,000
| New | +$175K |
|
4373
Trinity Capital Inc.
TRIN
$1.58B
| $173K | ﹤0.01% |
+11,800
| New | +$176K |
|
4374
CALL
Stem
STEM
$44.3M
| $173K | ﹤0.01% |
650,500
-9,000
| -1% | -$172K |
|
4375
NeoGenomics
NEO
$1.99B
| $173K | ﹤0.01% |
14,691
-9,071
| -38% | -$97.9K |
|
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.