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 | |
|---|---|---|---|---|---|---|
3551
CALL
Seadrill
SDRL
$2.56B
| $388K | ﹤0.01% |
11,200
-3,000
| -21% | -$93.4K |
|
3552
PUT
Procept Biorobotics
PRCT
$1.03B
| $387K | ﹤0.01% |
12,300
+7,200
| +141% | +$239K |
|
3553
CALL
Prospect Capital
PSEC
$1.12B
| $387K | ﹤0.01% |
149,400
+9,600
| +7% | +$25.6K |
|
3554
CALL
Replimune Group
REPL
$449M
| $387K | ﹤0.01% |
39,800
-30,500
| -43% | -$259K |
|
3555
US Global Jets ETF
JETS
$790M
| $387K | ﹤0.01% |
+13,773
| New | +$358K |
|
|
ALMS
3556
CALL
Alumis Inc
ALMS
$3.45B
| $386K | ﹤0.01% |
39,600
+36,800
| +1,314% | +$257K |
|
3557
CALL
ARK 21Shares Bitcoin ETF
ARKB
$2.43B
| $386K | ﹤0.01% |
13,300
-44,900
| -77% | -$1.49M |
|
3558
CALL
Relay Therapeutics
RLAY
$3.99B
| $386K | ﹤0.01% |
45,600
-3,200
| -7% | -$22.8K |
|
3559
PUT
Avista
AVA
$3.46B
| $385K | ﹤0.01% |
10,000
+8,600
| +614% | +$336K |
|
3560
Direxion Daily Aerospace & Defense Bull 3X ETF
DFEN
$413M
| $385K | ﹤0.01% |
+6,025
| New | +$396K |
|
3561
PUT
Zymeworks
ZYME
$1.66B
| $384K | ﹤0.01% |
14,600
+12,800
| +711% | +$279K |
|
3562
Curtiss-Wright
CW
$26.9B
| $384K | ﹤0.01% |
697
-555
| -44% | -$310K |
|
3563
CALL
Vuzix
VUZI
$187M
| $384K | ﹤0.01% |
101,600
-18,000
| -15% | -$56.6K |
|
3564
CALL
Fortress Biotech
FBIO
$113M
| $384K | ﹤0.01% |
104,800
+38,200
| +57% | +$109K |
|
3565
CALL
Lincoln Electric
LECO
$14.6B
| $383K | ﹤0.01% |
1,600
-1,400
| -47% | -$332K |
|
3566
CALL
PTC
PTC
$14.7B
| $383K | ﹤0.01% |
2,200
+1,800
| +450% | +$334K |
|
|
NGD
3567
PUT
DELISTED
New Gold Inc
NGD
| $383K | ﹤0.01% |
44,000
-129,500
| -75% | -$975K |
|
3568
Lightpath Technologies
LPTH
$651M
| $383K | ﹤0.01% |
35,472
-24,404
| -41% | -$198K |
|
3569
CALL
Green Brick Partners
GRBK
$3.18B
| $382K | ﹤0.01% |
6,100
+5,300
| +663% | +$349K |
|
3570
CALL
Pegasystems
PEGA
$4.85B
| $382K | ﹤0.01% |
6,400
-2,600
| -29% | -$152K |
|
|
AIFC
3571
CALL
AI Financial Corp
AIFC
$54.9M
| $382K | ﹤0.01% |
347,400
-411,200
| -54% | -$792K |
|
3572
Xylem
XYL
$29.7B
| $382K | ﹤0.01% |
2,805
+2,392
| +579% | +$344K |
|
3573
MoonLake Immunotherapeutics
MLTX
$1.59B
| $382K | ﹤0.01% |
28,972
-29,257
| -50% | -$345K |
|
3574
CALL
Ecopetrol
EC
$32.5B
| $382K | ﹤0.01% |
38,100
-41,100
| -52% | -$392K |
|
3575
Campbell Soup
CPB
$6.8B
| $382K | ﹤0.01% |
13,697
-24,721
| -64% | -$743K |
|
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.