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 | |
|---|---|---|---|---|---|---|
4851
CALL
Senseonics Holdings Inc
SENS
$265M
| $116K | ﹤0.01% |
21,000
+18,885
| +893% | +$131K |
|
|
ORC
4852
Orchid Island Capital
ORC
$1.32B
| $116K | ﹤0.01% |
16,078
+15,802
| +5,725% | +$115K |
|
4853
CALL
TaskUs
TASK
$542M
| $116K | ﹤0.01% |
9,800
+8,100
| +476% | +$104K |
|
4854
CALL
Yelp
YELP
$1.44B
| $115K | ﹤0.01% |
3,800
+2,900
| +322% | +$89.4K |
|
|
AUTL
4855
Autolus Therapeutics
AUTL
$407M
| $115K | ﹤0.01% |
57,919
+44,366
| +327% | +$68.2K |
|
4856
CALL
Portland General Electric
POR
$5.8B
| $115K | ﹤0.01% |
2,400
-4,100
| -63% | -$194K |
|
4857
Innoviz Technologies
INVZ
$93.2M
| $115K | ﹤0.01% |
134,774
-212,639
| -61% | -$337K |
|
|
TECX
4858
CALL
Tectonic Therapeutic
TECX
$538M
| $115K | ﹤0.01% |
5,500
+3,600
| +189% | +$66.9K |
|
4859
PUT
Revolve Group
RVLV
$1.82B
| $115K | ﹤0.01% |
3,800
-18,700
| -83% | -$452K |
|
4860
PUT
Kodiak Sciences
KOD
$2.66B
| $115K | ﹤0.01% |
4,100
+3,300
| +413% | +$67.6K |
|
4861
L3Harris
LHX
$50.7B
| $114K | ﹤0.01% |
+390
| New | +$113K |
|
|
LAZR
4862
PUT
DELISTED
Luminar Technologies
LAZR
| $114K | ﹤0.01% |
1,431,000
+1,260,500
| +739% | +$1.65M |
|
4863
CALL
Macerich
MAC
$7.22B
| $114K | ﹤0.01% |
6,200
-4,600
| -43% | -$81.1K |
|
|
BCAX
4864
PUT
Bicara Therapeutics
BCAX
$1.73B
| $114K | ﹤0.01% |
6,800
-400
| -6% | -$6.83K |
|
4865
CALL
RCI Hospitality Holdings
RICK
$197M
| $114K | ﹤0.01% |
4,800
-62,400
| -93% | -$1.6M |
|
4866
Bentley Systems
BSY
$10.7B
| $114K | ﹤0.01% |
+2,994
| New | +$136K |
|
4867
PUT
Kanzhun
BZ
$7.33B
| $114K | ﹤0.01% |
5,600
-64,000
| -92% | -$1.38M |
|
4868
CALL
Vulcan Materials
VMC
$35.2B
| $114K | ﹤0.01% |
400
-3,700
| -90% | -$1.09M |
|
4869
CALL
Cato Corp
CATO
$66.5M
| $114K | ﹤0.01% |
36,900
-56,000
| -60% | -$206K |
|
4870
iPath Series B S&P 500 VIX Mid-Term Futures ETN
VXZ
$31.1M
| $113K | ﹤0.01% |
2,121
+1,120
| +112% | +$62.8K |
|
4871
Liberty Global Class A
LBTYA
$3.56B
| $113K | ﹤0.01% |
10,172
-30,517
| -75% | -$338K |
|
|
TPH
4872
PUT
DELISTED
Tri Pointe Homes
TPH
| $113K | ﹤0.01% |
3,600
+3,400
| +1,700% | +$111K |
|
|
DOO
4873
PUT
Bombardier Recreational Products
DOO
$4.58B
| $113K | ﹤0.01% |
+1,600
| New | +$109K |
|
4874
ProShares UltraPro Dow 30
UDOW
$829M
| $113K | ﹤0.01% |
+1,954
| New | +$109K |
|
4875
CALL
Caribou Biosciences
CRBU
$150M
| $113K | ﹤0.01% |
71,000
+63,500
| +847% | +$133K |
|
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.