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 | |
|---|---|---|---|---|---|---|
5151
CALL
Delcath Systems
DCTH
$422M
| $85.8K | ﹤0.01% |
8,500
-6,300
| -43% | -$62.6K |
|
5152
CALL
Verastem
VSTM
$510M
| $85.7K | ﹤0.01% |
11,100
-5,100
| -31% | -$45.5K |
|
5153
CALL
Ecovyst
ECVT
$1.32B
| $85.6K | ﹤0.01% |
+8,800
| New | +$76.8K |
|
5154
CALL
Kymera Therapeutics
KYMR
$8.51B
| $85.6K | ﹤0.01% |
1,100
-1,900
| -63% | -$128K |
|
5155
PUT
Marqeta
MQ
$1.83B
| $85.5K | ﹤0.01% |
4,500
+25
| +0.6% | +$480 |
|
5156
Immuneering
IMRX
$267M
| $85.2K | ﹤0.01% |
+12,950
| New | +$83.1K |
|
|
LTC
5157
LTC Properties
LTC
$2.06B
| $85.2K | ﹤0.01% |
2,477
-2,139
| -46% | -$75.4K |
|
5158
CALL
Ventas
VTR
$48B
| $85.1K | ﹤0.01% |
1,100
-18,500
| -94% | -$1.4M |
|
5159
CALL
Assembly Biosciences
ASMB
$498M
| $85K | ﹤0.01% |
2,500
+2,300
| +1,150% | +$74.1K |
|
5160
PUT
American Well
AMWL
$180M
| $84.9K | ﹤0.01% |
+17,300
| New | +$83.4K |
|
5161
Vera Bradley
VRA
$97M
| $84.9K | ﹤0.01% |
35,083
+12,442
| +55% | +$28.9K |
|
5162
PUT
Absci
ABSI
$1.32B
| $84.8K | ﹤0.01% |
24,300
-53,000
| -69% | -$193K |
|
5163
CALL
SI-BONE Inc
SIBN
$788M
| $84.8K | ﹤0.01% |
4,300
-6,100
| -59% | -$106K |
|
5164
CALL
Danaos Corp
DAC
$2.58B
| $84.8K | ﹤0.01% |
900
-500
| -36% | -$46.1K |
|
|
PPTA
5165
Perpetua Resources
PPTA
$2.3B
| $84.6K | ﹤0.01% |
3,493
-44,224
| -93% | -$1.09M |
|
5166
Brookfield Infrastructure Partners
BIP
$19.2B
| $84.6K | ﹤0.01% |
2,434
-5,387
| -69% | -$188K |
|
5167
PUT
Contango Silver & Gold Inc
CTGO
$516M
| $84.5K | ﹤0.01% |
3,200
+2,100
| +191% | +$51.4K |
|
5168
Barnes & Noble Education
BNED
$431M
| $84.4K | ﹤0.01% |
9,186
+8,700
| +1,790% | +$76.8K |
|
5169
PUT
RenaissanceRe
RNR
$13.3B
| $84.3K | ﹤0.01% |
300
-300
| -50% | -$78.9K |
|
|
SJT
5170
PUT
San Juan Basin Royalty Trust
SJT
$117M
| $84.3K | ﹤0.01% |
15,000
-3,700
| -20% | -$21.4K |
|
|
5171
CALL
Immuneering
IMRX
$267M
| $84.2K | ﹤0.01% |
+12,800
| New | +$82.2K |
|
5172
Sagimet Biosciences
SGMT
$439M
| $84.2K | ﹤0.01% |
+14,227
| New | +$102K |
|
5173
CALL
Trex
TREX
$4.51B
| $84.2K | ﹤0.01% |
2,400
-1,100
| -31% | -$44.5K |
|
5174
PUT
W.R. Berkley
WRB
$26.9B
| $84.1K | ﹤0.01% |
1,200
+500
| +71% | +$36.8K |
|
|
ACH
5175
Accendra Health
ACH
$237M
| $83.8K | ﹤0.01% |
29,943
-3,227
| -10% | -$11.5K |
|
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.