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 | |
|---|---|---|---|---|---|---|
3126
CALL
Omega Healthcare
OHI
$15.3B
| $599K | ﹤0.01% |
13,500
-3,300
| -20% | -$142K |
|
|
TWO
3127
Two Harbors Investment
TWO
$1.27B
| $598K | ﹤0.01% |
56,994
-23,831
| -29% | -$238K |
|
3128
CALL
ARS Pharmaceuticals
SPRY
$572M
| $598K | ﹤0.01% |
51,300
+16,400
| +47% | +$159K |
|
3129
PUT
Louisiana-Pacific
LPX
$5.19B
| $598K | ﹤0.01% |
7,400
-4,000
| -35% | -$338K |
|
3130
NiSource
NI
$22B
| $597K | ﹤0.01% |
14,299
-24,766
| -63% | -$1.06M |
|
3131
Prosperity Bancshares
PB
$8.69B
| $597K | ﹤0.01% |
+8,639
| New | +$583K |
|
3132
CALL
Murphy Oil
MUR
$5.38B
| $597K | ﹤0.01% |
19,100
+2,200
| +13% | +$66.2K |
|
3133
PUT
SM Energy
SM
$7.26B
| $597K | ﹤0.01% |
31,900
-38,700
| -55% | -$784K |
|
|
DVAX
3134
PUT
DELISTED
Dynavax Technologies
DVAX
| $592K | ﹤0.01% |
38,500
+35,700
| +1,275% | +$393K |
|
3135
PUT
Listed Funds Trust Roundhill Magnificent Seven ETF
MAGS
$3.8B
| $592K | ﹤0.01% |
14,100
-61,300
| -81% | -$4.05M |
|
3136
CALL
Liberty Media Series A
FWONA
$22.6B
| $591K | ﹤0.01% |
+6,000
| New | +$538K |
|
3137
PUT
ImmunityBio
IBRX
$7.32B
| $591K | ﹤0.01% |
298,300
+154,200
| +107% | +$349K |
|
3138
PUT
Alight
ALIT
$520M
| $590K | ﹤0.01% |
15,135
+14,760
| +3,936% | +$735K |
|
3139
Trevi Therapeutics
TRVI
$2.57B
| $590K | ﹤0.01% |
47,134
-16,015
| -25% | -$185K |
|
3140
Oshkosh
OSK
$9.66B
| $590K | ﹤0.01% |
+4,694
| New | +$604K |
|
3141
CALL
Kura Oncology
KURA
$901M
| $589K | ﹤0.01% |
56,700
+40,100
| +242% | +$421K |
|
3142
PUT
Saia
SAIA
$11.2B
| $588K | ﹤0.01% |
1,800
-5,200
| -74% | -$1.57M |
|
3143
CALL
Prime Medicine
PRME
$544M
| $587K | ﹤0.01% |
169,300
+92,800
| +121% | +$413K |
|
|
CSW
3144
CALL
CSW Industrials
CSW
$4.78B
| $587K | ﹤0.01% |
+2,000
| New | +$533K |
|
3145
Celanese
CE
$4.87B
| $587K | ﹤0.01% |
+13,883
| New | +$566K |
|
3146
PUT
MasTec
MTZ
$26.6B
| $587K | ﹤0.01% |
2,700
-2,700
| -50% | -$567K |
|
3147
CALL
AdaptHealth
AHCO
$1.49B
| $587K | ﹤0.01% |
58,900
-2,700
| -4% | -$25.8K |
|
3148
CALL
Kosmos Energy
KOS
$1.45B
| $586K | ﹤0.01% |
645,900
-56,500
| -8% | -$74.5K |
|
3149
CALL
TKO Group
TKO
$13.7B
| $585K | ﹤0.01% |
2,800
-6,100
| -69% | -$1.19M |
|
3150
PUT
Rogers Communications
RCI
$17.7B
| $585K | ﹤0.01% |
15,500
-6,100
| -28% | -$229K |
|
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.