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 | |
|---|---|---|---|---|---|---|
4901
PUT
CNX Resources
CNX
$4.87B
| $110K | ﹤0.01% |
3,000
-900
| -23% | -$32.2K |
|
4902
CALL
Curtiss-Wright
CW
$26.6B
| $110K | ﹤0.01% |
200
-6,700
| -97% | -$3.74M |
|
4903
Park Aerospace
PKE
$738M
| $110K | ﹤0.01% |
5,165
+3,160
| +158% | +$63K |
|
4904
Harmonic Inc
HLIT
$1.24B
| $110K | ﹤0.01% |
11,141
-3,051
| -21% | -$30.7K |
|
4905
CALL
Dynagas LNG Partners
DLNG
$135M
| $110K | ﹤0.01% |
29,200
+700
| +2% | +$2.56K |
|
|
DVS
4906
DELISTED
Dolly Varden Silver Corp
DVS
| $110K | ﹤0.01% |
24,935
+20,365
| +446% | +$89.3K |
|
4907
CALL
Patria Investments
PAX
$1.76B
| $110K | ﹤0.01% |
6,900
-22,100
| -76% | -$331K |
|
4908
Kornit Digital
KRNT
$700M
| $110K | ﹤0.01% |
7,624
+7,490
| +5,590% | +$103K |
|
4909
Equinor
EQNR
$96.6B
| $110K | ﹤0.01% |
4,637
-20,128
| -81% | -$475K |
|
4910
Valmont Industries
VMI
$9.32B
| $109K | ﹤0.01% |
+272
| New | +$111K |
|
4911
CALL
Winnebago Industries
WGO
$849M
| $109K | ﹤0.01% |
2,700
-2,400
| -47% | -$87.5K |
|
4912
Goldman Sachs ETF Trust Goldman Sachs Nasdaq-100 Premium Income ETF
GPIQ
$4.96B
| $109K | ﹤0.01% |
2,065
+1,293
| +167% | +$68.3K |
|
4913
CALL
LXP Industrial Trust
LXP
$3.58B
| $109K | ﹤0.01% |
2,200
+2,000
| +1,000% | +$95.8K |
|
4914
Yum China
YUMC
$16.3B
| $109K | ﹤0.01% |
2,282
+564
| +33% | +$25.8K |
|
|
AL
4915
DELISTED
Air Lease Corp
AL
| $109K | ﹤0.01% |
1,696
-1,616
| -49% | -$103K |
|
4916
Taysha Gene Therapies
TSHA
$1.68B
| $109K | ﹤0.01% |
19,782
+17,060
| +627% | +$82.8K |
|
4917
CALL
Satellogic
SATL
$532M
| $109K | ﹤0.01% |
58,100
-45,700
| -44% | -$98.8K |
|
|
SMST
4918
CALL
Defiance Daily Target 2x Short MSTR ETF
SMST
$30.8M
| $108K | ﹤0.01% |
2,800
-16,100
| -85% | -$897K |
|
4919
PUT
Red Violet
RDVT
$969M
| $108K | ﹤0.01% |
+1,900
| New | +$103K |
|
4920
PUT
iShares iBonds 2030 Term High Yield and Income ETF
IBHJ
$151M
| $108K | ﹤0.01% |
1,900
-18,700
| -91% | -$497K |
|
4921
PUT
Compass Diversified
CODI
$758M
| $108K | ﹤0.01% |
22,500
+1,500
| +7% | +$9.48K |
|
|
NBP
4922
CALL
NovaBridge Biosciences American Depositary Shares
NBP
$187M
| $108K | ﹤0.01% |
27,100
-16,500
| -38% | -$73K |
|
4923
Kodak
KODK
$814M
| $108K | ﹤0.01% |
12,744
-20,175
| -61% | -$151K |
|
4924
CALL
Enliven Therapeutics
ELVN
$3.82B
| $108K | ﹤0.01% |
+7,000
| New | +$139K |
|
|
WDTE
4925
Defiance S&P 500 Weekly Distribution ETF
WDTE
$65.4M
| $108K | ﹤0.01% |
3,407
+2,983
| +704% | +$97.6K |
|
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.