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 | |
|---|---|---|---|---|---|---|
|
PSTL
4601
CALL
Postal Realty Trust
PSTL
$703M
| $142K | ﹤0.01% |
8,800
-5,900
| -40% | -$90.7K |
|
4602
iShares International Select Dividend ETF
IDV
$8.31B
| $142K | ﹤0.01% |
3,600
+3,427
| +1,981% | +$130K |
|
4603
BGC Group
BGC
$5.64B
| $142K | ﹤0.01% |
15,885
-26,925
| -63% | -$243K |
|
|
DENN
4604
CALL
DELISTED
Denny's
DENN
| $142K | ﹤0.01% |
22,800
+13,100
| +135% | +$74.3K |
|
4605
PTC
PTC
$15.3B
| $142K | ﹤0.01% |
814
+190
| +30% | +$35.3K |
|
|
BCYC
4606
Bicycle Therapeutics
BCYC
$269M
| $142K | ﹤0.01% |
+19,986
| New | +$147K |
|
4607
CALL
Ameris Bancorp
ABCB
$5.89B
| $141K | ﹤0.01% |
1,900
+1,700
| +850% | +$127K |
|
4608
Napco Security Technologies
NSSC
$1.3B
| $141K | ﹤0.01% |
3,376
-1,334
| -28% | -$56.1K |
|
4609
CALL
Blink Charging
BLNK
$67.5M
| $141K | ﹤0.01% |
210,700
-104,800
| -33% | -$152K |
|
4610
FirstService
FSV
$6.55B
| $140K | ﹤0.01% |
+903
| New | +$147K |
|
4611
CALL
ePlus
PLUS
$2.43B
| $140K | ﹤0.01% |
+1,600
| New | +$132K |
|
|
VOYG
4612
Voyager Technologies
VOYG
$1.34B
| $140K | ﹤0.01% |
5,367
-5,073
| -49% | -$138K |
|
4613
CALL
Northwest Natural Holdings
NWN
$2.15B
| $140K | ﹤0.01% |
3,000
-600
| -17% | -$28K |
|
4614
CALL
Limbach Holdings
LMB
$807M
| $140K | ﹤0.01% |
1,800
-2,500
| -58% | -$206K |
|
4615
MDU Resources
MDU
$4.18B
| $140K | ﹤0.01% |
7,170
+6,722
| +1,500% | +$132K |
|
4616
CALL
NeoGenomics
NEO
$1.96B
| $140K | ﹤0.01% |
11,900
-30,800
| -72% | -$332K |
|
4617
PUT
Nano X Imaging
NNOX
$61.1M
| $140K | ﹤0.01% |
49,900
-96,800
| -66% | -$348K |
|
4618
PUT
Celcuity
CELC
$4.06B
| $140K | ﹤0.01% |
1,400
-800
| -36% | -$65.8K |
|
|
4619
PUT
PTC
PTC
$15.3B
| $139K | ﹤0.01% |
800
-2,500
| -76% | -$465K |
|
4620
Reliance Steel & Aluminium
RS
$20.6B
| $139K | ﹤0.01% |
482
+262
| +119% | +$73.6K |
|
4621
CALL
Matrix Service
MTRX
$312M
| $139K | ﹤0.01% |
11,900
-10,100
| -46% | -$127K |
|
4622
CALL
Trinity Capital Inc.
TRIN
$1.58B
| $139K | ﹤0.01% |
9,500
-1,900
| -17% | -$28.3K |
|
4623
CALL
ONE Gas
OGS
$5.01B
| $139K | ﹤0.01% |
1,800
+100
| +6% | +$8.04K |
|
4624
CALL
Customers Bancorp
CUBI
$2.66B
| $139K | ﹤0.01% |
1,900
+1,800
| +1,800% | +$123K |
|
4625
PUT
Invivyd
IVVD
$160M
| $139K | ﹤0.01% |
56,200
+3,500
| +7% | +$7.28K |
|
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.