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 |
Microsoft
MSFT
|
+$234M |
| 2 |
iShares Russell 2000 ETF
IWM
|
+$97.5M |
| 3 |
Amazon
AMZN
|
+$96.8M |
| 4 |
iShares Bitcoin Trust
IBIT
|
+$80.6M |
| 5 |
Pinduoduo
PDD
|
+$54.9M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
iShares 20+ Year Treasury Bond ETF
TLT
|
+$129M |
| 2 |
Alphabet (Google) Class A
GOOGL
|
+$92.9M |
| 3 |
Broadcom
AVGO
|
+$82.9M |
| 4 |
Alphabet (Google) Class C
GOOG
|
+$68.4M |
| 5 |
Meta Platforms (Facebook)
META
|
+$59.2M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 0.79% |
| 2 | Consumer Discretionary | 0.3% |
| 3 | Healthcare | 0.25% |
| 4 | Financials | 0.17% |
| 5 | Industrials | 0.09% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
2476
Tradeweb Markets
TW
$21.3B
| $1.72M | ﹤0.01% |
+15,524
| New | +$2M |
|
2477
CALL
Allegiant Air
ALGT
$2.64B
| $1.72M | ﹤0.01% |
28,300
-5,500
| -16% | -$315K |
|
2478
PUT
Chord Energy
CHRD
$7.79B
| $1.72M | ﹤0.01% |
17,300
+9,700
| +128% | +$1.02M |
|
2479
Grayscale Bitcoin Trust
GBTC
$9.64B
| $1.72M | ﹤0.01% |
+19,144
| New | +$1.72M |
|
2480
PUT
Burford Capital
BUR
$907M
| $1.71M | ﹤0.01% |
143,000
+59,600
| +71% | +$797K |
|
2481
CALL
Zevra Therapeutics
ZVRA
$563M
| $1.71M | ﹤0.01% |
179,900
+68,100
| +61% | +$683K |
|
2482
PUT
Axcelis
ACLS
$4.12B
| $1.71M | ﹤0.01% |
17,500
| – | – |
|
2483
CALL
Steris
STE
$20.9B
| $1.71M | ﹤0.01% |
6,900
+5,700
| +475% | +$1.36M |
|
|
SLNO
2484
DELISTED
Soleno Therapeutics
SLNO
| $1.7M | ﹤0.01% |
+25,109
| New | +$1.86M |
|
2485
ProShares Short Russell2000
RWM
$122M
| $1.7M | ﹤0.01% |
101,017
+100,260
| +13,244% | +$1.78M |
|
|
MIAX
2486
CALL
Miami International Holdings
MIAX
$4.14B
| $1.69M | ﹤0.01% |
+42,100
| New | +$1.54M |
|
2487
CALL
PagerDuty
PD
$700M
| $1.69M | ﹤0.01% |
102,500
+32,400
| +46% | +$515K |
|
2488
CALL
Knight Transportation
KNX
$11.8B
| $1.69M | ﹤0.01% |
42,800
+4,600
| +12% | +$199K |
|
2489
NiSource
NI
$22.4B
| $1.69M | ﹤0.01% |
39,065
+17,819
| +84% | +$738K |
|
2490
PUT
Corcept Therapeutics
CORT
$10.2B
| $1.69M | ﹤0.01% |
20,300
-42,300
| -68% | -$3.06M |
|
|
JOYY
2491
CALL
JOYY Inc
JOYY
$3.73B
| $1.69M | ﹤0.01% |
28,800
+3,500
| +14% | +$192K |
|
2492
CALL
Alphatec Holdings
ATEC
$1.27B
| $1.68M | ﹤0.01% |
115,800
+10,500
| +10% | +$146K |
|
2493
CALL
VeriSign
VRSN
$25.3B
| $1.68M | ﹤0.01% |
6,000
-4,200
| -41% | -$1.17M |
|
2494
Datadog
DDOG
$87.9B
| $1.68M | ﹤0.01% |
+11,770
| New | +$1.62M |
|
2495
CALL
Mid-America Apartment Communities
MAA
$15.6B
| $1.68M | ﹤0.01% |
12,000
+11,500
| +2,300% | +$1.66M |
|
2496
PUT
State Street
STT
$50.9B
| $1.67M | ﹤0.01% |
14,400
-6,000
| -29% | -$670K |
|
|
HNGE
2497
CALL
Hinge Health
HNGE
$5.75B
| $1.67M | ﹤0.01% |
34,000
+14,600
| +75% | +$764K |
|
2498
CALL
Sprouts Farmers Market
SFM
$7.04B
| $1.66M | ﹤0.01% |
15,300
-3,500
| -19% | -$509K |
|
2499
CALL
PACS Group
PACS
$7.42B
| $1.66M | ﹤0.01% |
121,200
+108,600
| +862% | +$1.27M |
|
2500
Advanced Micro Devices
AMD
$851B
| $1.66M | ﹤0.01% |
10,275
-331,733
| -97% | -$53.5M |
|
Similar funds
Simplex Trading's Q3 2025 Portfolio in Review
As of Q3 2025, Simplex Trading held 10,358 positions worth $195B, up 12% from $175B the previous quarter. Its ten largest holdings account for 46% of the portfolio.
Simplex Trading's Q3 2025 filing shows 1,743 new, 3,828 increased, 3,250 reduced and 1,308 closed positions. Its largest new stake was Microsoft: 458,309 shares worth $237M. The largest sale was iShares 20+ Year Treasury Bond ETF, an estimated $129M.
By sector, the portfolio is most concentrated in Technology at 0.79% of assets, up from 0.74% a quarter earlier, followed by Consumer Discretionary and Healthcare.
- Simplex Trading's largest Q3 2025 buy was Microsoft: 458,309 shares worth $237M.
- Simplex Trading added most to iShares Russell 2000 ETF in Q3 2025, an estimated $97.5M increase.
- Simplex Trading's biggest Q3 2025 reduction was Alphabet (Google) Class A, cutting an estimated $92.9M.
- Simplex Trading fully exited iShares 20+ Year Treasury Bond ETF in Q3 2025, selling an estimated $129M.
- Simplex Trading's ten largest holdings make up 46% of its $195B portfolio in Q3 2025.
- Simplex Trading opened 1,743 new positions and closed 1,308 in Q3 2025.
- Simplex Trading's portfolio value rose 12% quarter-over-quarter to $195B.
Based on Simplex Trading's 13F filing for Q3 2025, filed 12 Nov 2025.