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 | |
|---|---|---|---|---|---|---|
3376
PUT
Strive Inc
ASST
$1.01B
| $463K | ﹤0.01% |
31,395
-44,635
| -59% | -$1.07M |
|
3377
CALL
Honda
HMC
$39.2B
| $463K | ﹤0.01% |
15,700
-29,500
| -65% | -$896K |
|
|
PSIX
3378
PUT
Power Solutions International
PSIX
$639M
| $463K | ﹤0.01% |
8,100
+2,100
| +35% | +$150K |
|
3379
Thryv Holdings
THRY
$188M
| $463K | ﹤0.01% |
76,496
+74,526
| +3,783% | +$590K |
|
3380
Under Armour Class C
UA
$2.95B
| $463K | ﹤0.01% |
96,399
-5,473
| -5% | -$24.3K |
|
3381
CALL
Elbit Systems
ESLT
$38.5B
| $462K | ﹤0.01% |
800
-1,500
| -65% | -$752K |
|
3382
PUT
Perrigo
PRGO
$1.42B
| $462K | ﹤0.01% |
33,200
+10,600
| +47% | +$177K |
|
3383
PUT
iRhythm Holdings
IRTC
$3.83B
| $461K | ﹤0.01% |
2,600
+1,300
| +100% | +$230K |
|
3384
PUT
Rambus
RMBS
$9.55B
| $459K | ﹤0.01% |
5,000
-20,600
| -80% | -$2.03M |
|
3385
PUT
CorMedix
CRMD
$575M
| $459K | ﹤0.01% |
39,500
-66,400
| -63% | -$734K |
|
3386
CALL
Mid-America Apartment Communities
MAA
$15.8B
| $458K | ﹤0.01% |
3,300
-8,700
| -73% | -$1.16M |
|
3387
CALL
ADT
ADT
$5.34B
| $458K | ﹤0.01% |
56,800
-69,500
| -55% | -$578K |
|
|
HTT
3388
High Templar Tech Ltd
HTT
$382M
| $458K | ﹤0.01% |
129,091
-83,506
| -39% | -$373K |
|
|
RZLV
3389
PUT
Rezolve AI
RZLV
$913M
| $458K | ﹤0.01% |
178,200
-97,500
| -35% | -$368K |
|
3390
CALL
Inovio Pharmaceuticals
INO
$82M
| $457K | ﹤0.01% |
262,900
-134,200
| -34% | -$296K |
|
3391
CALL
USA Compression Partners
USAC
$3.75B
| $455K | ﹤0.01% |
19,800
-2,300
| -10% | -$54K |
|
3392
CALL
Sprout Social
SPT
$526M
| $455K | ﹤0.01% |
40,400
+37,700
| +1,396% | +$407K |
|
3393
CALL
TransUnion
TRU
$16.5B
| $454K | ﹤0.01% |
5,300
+100
| +2% | +$8.22K |
|
3394
PUT
ARS Pharmaceuticals
SPRY
$574M
| $454K | ﹤0.01% |
39,000
-12,700
| -25% | -$124K |
|
|
SLNO
3395
CALL
DELISTED
Soleno Therapeutics
SLNO
| $454K | ﹤0.01% |
9,800
-75,000
| -88% | -$4.11M |
|
3396
Surgery Partners
SGRY
$2.05B
| $454K | ﹤0.01% |
+29,357
| New | +$540K |
|
3397
Stoke Therapeutics
STOK
$1.81B
| $453K | ﹤0.01% |
+14,281
| New | +$429K |
|
3398
Nurix Therapeutics
NRIX
$2.39B
| $453K | ﹤0.01% |
23,885
+9,440
| +65% | +$136K |
|
3399
CALL
Northern Oil and Gas
NOG
$2.16B
| $453K | ﹤0.01% |
21,100
+1,400
| +7% | +$31.4K |
|
3400
CALL
Service Corp International
SCI
$11.8B
| $452K | ﹤0.01% |
5,800
+1,700
| +41% | +$136K |
|
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.