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 | |
|---|---|---|---|---|---|---|
3801
SGHC Ltd
SGHC
$7.62B
| $303K | ﹤0.01% |
25,379
-191,045
| -88% | -$2.3M |
|
3802
CALL
Cooper Companies
COO
$14.1B
| $303K | ﹤0.01% |
3,700
-6,600
| -64% | -$494K |
|
3803
CALL
Jack in the Box
JACK
$308M
| $303K | ﹤0.01% |
16,000
-10,300
| -39% | -$186K |
|
|
PMT
3804
PennyMac Mortgage Investment
PMT
$854M
| $303K | ﹤0.01% |
+24,145
| New | +$301K |
|
3805
Cooper-Standard Automotive
CPS
$526M
| $303K | ﹤0.01% |
9,225
-89,908
| -91% | -$2.93M |
|
3806
PUT
Vanda Pharmaceuticals
VNDA
$310M
| $303K | ﹤0.01% |
34,300
-101,000
| -75% | -$556K |
|
|
ONIT
3807
CALL
Onity Group
ONIT
$341M
| $302K | ﹤0.01% |
6,600
-100
| -1% | -$4.11K |
|
3808
PUT
Fulgent Genetics
FLGT
$558M
| $302K | ﹤0.01% |
11,500
+11,300
| +5,650% | +$293K |
|
3809
PUT
Hudbay
HBM
$9.67B
| $302K | ﹤0.01% |
15,200
-8,300
| -35% | -$140K |
|
3810
CALL
Ingles Markets
IMKTA
$1.71B
| $302K | ﹤0.01% |
4,400
+3,400
| +340% | +$247K |
|
3811
CALL
Lightspeed Commerce
LSPD
$1.41B
| $301K | ﹤0.01% |
24,900
-7,400
| -23% | -$87.6K |
|
3812
PUT
MaxLinear
MXL
$5.35B
| $300K | ﹤0.01% |
17,200
-3,600
| -17% | -$58.6K |
|
3813
CALL
Ardelyx
ARDX
$1.25B
| $300K | ﹤0.01% |
51,400
-12,000
| -19% | -$66.8K |
|
3814
PUT
FLEX LNG
FLNG
$1.67B
| $299K | ﹤0.01% |
12,000
-3,900
| -25% | -$99.4K |
|
3815
CALL
Charles River Laboratories
CRL
$11.6B
| $299K | ﹤0.01% |
1,500
-5,100
| -77% | -$925K |
|
3816
PUT
Grupo Cibest SA
CIB
$21.1B
| $299K | ﹤0.01% |
4,700
+4,300
| +1,075% | +$257K |
|
3817
PUT
Phibro Animal Health
PAHC
$1.48B
| $299K | ﹤0.01% |
8,000
+4,900
| +158% | +$199K |
|
3818
CALL
PBF Energy
PBF
$7.22B
| $298K | ﹤0.01% |
11,000
-16,900
| -61% | -$541K |
|
3819
PUT
Cabot Corp
CBT
$4.7B
| $298K | ﹤0.01% |
4,500
+700
| +18% | +$46.6K |
|
|
NNDM
3820
CALL
Nano Dimension
NNDM
$314M
| $298K | ﹤0.01% |
193,500
+101,300
| +110% | +$172K |
|
|
GLDB
3821
PUT
IDX Alternative FIAT ETF
GLDB
$33.6M
| $297K | ﹤0.01% |
+51,400
| New | +$1.23M |
|
3822
PUT
TransAlta
TAC
$4.03B
| $297K | ﹤0.01% |
23,500
+14,800
| +170% | +$221K |
|
3823
PUT
Alphatec Holdings
ATEC
$1.43B
| $297K | ﹤0.01% |
14,100
+6,400
| +83% | +$118K |
|
|
DEA
3824
PUT
Easterly Government Properties
DEA
$1.17B
| $297K | ﹤0.01% |
14,000
+5,500
| +65% | +$119K |
|
3825
CALL
Cardiff Oncology
CRDF
$63.6M
| $296K | ﹤0.01% |
105,500
+53,600
| +103% | +$124K |
|
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.