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 | |
|---|---|---|---|---|---|---|
7651
CALL
Core Laboratories
CLB
$470M
| $3.21K | ﹤0.01% |
200
-3,500
| -95% | -$52.1K |
|
7652
CALL
WaFd
WAFD
$2.72B
| $3.2K | ﹤0.01% |
100
-100
| -50% | -$3.09K |
|
7653
CALL
Talphera
TLPH
$66.4M
| $3.19K | ﹤0.01% |
+2,800
| New | +$3.38K |
|
7654
KraneShares Global Carbon Strategy ETF
KRBN
$139M
| $3.19K | ﹤0.01% |
+90
| New | +$3.07K |
|
|
HTO
7655
H2O America
HTO
$2.66B
| $3.18K | ﹤0.01% |
65
-228
| -78% | -$10.9K |
|
7656
CALL
York Water
YORW
$513M
| $3.18K | ﹤0.01% |
100
| – | – |
|
7657
Global X FinTech ETF
FINX
$172M
| $3.18K | ﹤0.01% |
+108
| New | +$3.43K |
|
7658
PUT
Patria Investments
PAX
$1.73B
| $3.18K | ﹤0.01% |
200
-600
| -75% | -$8.98K |
|
7659
Cosmos Holdings
COSM
$11.8M
| $3.17K | ﹤0.01% |
6,374
+4,640
| +268% | +$3.45K |
|
7660
CALL
Oportun Financial
OPRT
$264M
| $3.17K | ﹤0.01% |
600
-4,000
| -87% | -$21.1K |
|
7661
PUT
Sight Sciences
SGHT
$291M
| $3.17K | ﹤0.01% |
+400
| New | +$2.56K |
|
7662
NanoViricides
NNVC
$40M
| $3.17K | ﹤0.01% |
2,803
+693
| +33% | +$973 |
|
7663
PUT
Paymentus
PAY
$4.49B
| $3.16K | ﹤0.01% |
100
-1,600
| -94% | -$52.2K |
|
|
BFS
7664
PUT
Saul Centers
BFS
$864M
| $3.15K | ﹤0.01% |
100
-100
| -50% | -$3.07K |
|
|
TPH
7665
CALL
DELISTED
Tri Pointe Homes
TPH
| $3.15K | ﹤0.01% |
100
-3,100
| -97% | -$101K |
|
7666
PUT
OraSure Technologies
OSUR
$273M
| $3.15K | ﹤0.01% |
+1,300
| New | +$3.42K |
|
|
WHWK
7667
CALL
Whitehawk Therapeutics
WHWK
$181M
| $3.15K | ﹤0.01% |
+1,300
| New | +$2.98K |
|
7668
PUT
Voyager Therapeutics
VYGR
$184M
| $3.14K | ﹤0.01% |
+800
| New | +$3.54K |
|
7669
iShares 5-10 Year Investment Grade Corporate Bond ETF
IGIB
$18.5B
| $3.13K | ﹤0.01% |
58
+11
| +23% | +$595 |
|
7670
iRadimed
IRMD
$1.21B
| $3.11K | ﹤0.01% |
32
-223
| -87% | -$19.1K |
|
7671
CALL
Prudential
PUK
$36.6B
| $3.11K | ﹤0.01% |
100
-10,800
| -99% | -$310K |
|
7672
ProShares UltraShort Consumer Staples
SZK
$8.49M
| $3.11K | ﹤0.01% |
121
+9
| +8% | +$231 |
|
7673
PUT
Columbia Financial
CLBK
$1.14B
| $3.11K | ﹤0.01% |
200
-2,800
| -93% | -$43.4K |
|
7674
PUT
XBiotech
XBIT
$68.6M
| $3.11K | ﹤0.01% |
1,300
| – | – |
|
7675
American Vanguard Corp
AVD
$71.8M
| $3.09K | ﹤0.01% |
810
-916
| -53% | -$4.28K |
|
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.