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 | |
|---|---|---|---|---|---|---|
|
LB
4726
PUT
LandBridge Co
LB
$2.13B
| $127K | ﹤0.01% |
2,600
-2,900
| -53% | -$169K |
|
4727
PUT
Equity Lifestyle Properties
ELS
$12.7B
| $127K | ﹤0.01% |
2,100
+1,400
| +200% | +$86.5K |
|
4728
Vanguard Consumer Discretionary ETF
VCR
$5.98B
| $127K | ﹤0.01% |
323
+262
| +430% | +$103K |
|
4729
CALL
BlackLine
BL
$1.8B
| $127K | ﹤0.01% |
2,300
-3,800
| -62% | -$209K |
|
4730
CALL
Open Text
OTEX
$6.15B
| $127K | ﹤0.01% |
3,900
+300
| +8% | +$10.7K |
|
4731
Kosmos Energy
KOS
$1.52B
| $127K | ﹤0.01% |
139,947
-241,014
| -63% | -$318K |
|
4732
CALL
Steris
STE
$22.5B
| $127K | ﹤0.01% |
500
-6,400
| -93% | -$1.61M |
|
4733
CALL
Bioventus
BVS
$893M
| $126K | ﹤0.01% |
17,000
+8,900
| +110% | +$64K |
|
4734
SPX Corp
SPXC
$9.98B
| $126K | ﹤0.01% |
632
+569
| +903% | +$116K |
|
4735
PUT
Lloyds Banking Group
LYG
$90.7B
| $126K | ﹤0.01% |
23,800
+12,900
| +118% | +$62.5K |
|
4736
CALL
Globe Life
GL
$14.2B
| $126K | ﹤0.01% |
900
-2,000
| -69% | -$271K |
|
4737
PUT
Assured Guaranty
AGO
$3.73B
| $126K | ﹤0.01% |
1,400
+100
| +8% | +$8.62K |
|
4738
CALL
Oshkosh
OSK
$8.82B
| $126K | ﹤0.01% |
1,000
-1,700
| -63% | -$219K |
|
4739
Allegion
ALLE
$13.4B
| $126K | ﹤0.01% |
789
+201
| +34% | +$33.5K |
|
4740
Greif
GEF
$4.96B
| $125K | ﹤0.01% |
1,853
+1,582
| +584% | +$99.1K |
|
4741
CALL
Labcorp
LH
$25.9B
| $125K | ﹤0.01% |
500
-5,100
| -91% | -$1.35M |
|
4742
PUT
Aldeyra Therapeutics
ALDX
$96.5M
| $125K | ﹤0.01% |
24,200
+4,300
| +22% | +$22.1K |
|
4743
AutoNation
AN
$7.18B
| $125K | ﹤0.01% |
607
-259
| -30% | -$53.9K |
|
4744
PUT
PagSeguro Digital
PAGS
$2.75B
| $125K | ﹤0.01% |
13,000
-105,500
| -89% | -$1.01M |
|
4745
CALL
Energizer
ENR
$1.44B
| $125K | ﹤0.01% |
6,300
-3,100
| -33% | -$67.6K |
|
4746
CALL
Zai Lab
ZLAB
$2.06B
| $125K | ﹤0.01% |
7,100
-26,400
| -79% | -$618K |
|
|
BLD
4747
PUT
DELISTED
TopBuild
BLD
| $125K | ﹤0.01% |
300
-200
| -40% | -$85.7K |
|
4748
PUT
Boise Cascade
BCC
$2.65B
| $125K | ﹤0.01% |
1,700
-8,900
| -84% | -$649K |
|
4749
PUT
Crexendo
CXDO
$221M
| $125K | ﹤0.01% |
19,300
-23,400
| -55% | -$153K |
|
4750
T. Rowe Price
TROW
$25.6B
| $125K | ﹤0.01% |
+1,219
| New | +$126K |
|
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.