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 | |
|---|---|---|---|---|---|---|
5276
CALL
iShares Core Dividend ETF
DIVB
$1.69B
| $149K | ﹤0.01% |
3,500
+2,600
| +289% | +$133K |
|
5277
PUT
1-800-Flowers.com
FLWS
$250M
| $149K | ﹤0.01% |
32,600
+32,100
| +6,420% | +$177K |
|
5278
CALL
Gencor Industries
GENC
$209M
| $149K | ﹤0.01% |
+10,200
| New | +$154K |
|
5279
iShares S&P GSCI Commodity-Indexed Trust
GSG
$998M
| $149K | ﹤0.01% |
+6,489
| New | +$147K |
|
5280
CALL
Itron
ITRI
$4.36B
| $149K | ﹤0.01% |
1,200
+1,100
| +1,100% | +$140K |
|
5281
CALL
JELD-WEN Holding
JELD
$122M
| $149K | ﹤0.01% |
30,500
+13,700
| +82% | +$73.3K |
|
5282
CALL
Jones Lang LaSalle
JLL
$16.5B
| $149K | ﹤0.01% |
500
+400
| +400% | +$114K |
|
5283
PUT
LCI Industries
LCII
$2.49B
| $149K | ﹤0.01% |
1,600
-300
| -16% | -$30K |
|
|
MAPS
5284
CALL
DELISTED
WM TECHNOLOGY INC A
MAPS
| $149K | ﹤0.01% |
129,100
-191,800
| -60% | -$207K |
|
5285
PUT
MACOM Technology Solutions
MTSI
$19.2B
| $149K | ﹤0.01% |
1,200
+800
| +200% | +$106K |
|
5286
PUT
Alector
ALEC
$168M
| $148K | ﹤0.01% |
+50,200
| New | +$111K |
|
5287
CALL
Alpha Pro Tech
APT
$50.4M
| $148K | ﹤0.01% |
31,100
-36,700
| -54% | -$176K |
|
5288
PUT
Ardelyx
ARDX
$1.22B
| $148K | ﹤0.01% |
26,900
-2,200
| -8% | -$11.9K |
|
5289
EXL Service
EXLS
$5.14B
| $148K | ﹤0.01% |
+3,383
| New | +$146K |
|
5290
Innovative Solutions & Support
ISSC
$327M
| $148K | ﹤0.01% |
11,859
-367
| -3% | -$5.12K |
|
5291
PUT
Microvision
MVIS
$93.2M
| $148K | ﹤0.01% |
120,000
-9,000
| -7% | -$10.7K |
|
5292
PUT
NovaGold Resources
NG
$2.56B
| $148K | ﹤0.01% |
16,900
+9,400
| +125% | +$57.5K |
|
5293
Stellus Capital Investment Corp
SCM
$217M
| $148K | ﹤0.01% |
11,335
+4,316
| +61% | +$62.2K |
|
5294
PUT
Tucows
TCX
$172M
| $148K | ﹤0.01% |
8,000
-600
| -7% | -$11.6K |
|
5295
CALL
Viridian Therapeutics
VRDN
$2.09B
| $148K | ﹤0.01% |
6,900
-12,100
| -64% | -$218K |
|
|
WCC
5296
PUT
WESCO International
WCC
$16.7B
| $148K | ﹤0.01% |
700
-2,000
| -74% | -$420K |
|
|
SRTA
5297
CALL
Strata Critical Medical Inc
SRTA
$434M
| $147K | ﹤0.01% |
29,100
+25,900
| +809% | +$114K |
|
|
CSR
5298
CALL
Centerspace
CSR
$921M
| $147K | ﹤0.01% |
+2,500
| New | +$144K |
|
5299
CALL
InflaRx
IFRX
$250M
| $147K | ﹤0.01% |
+110,000
| New | +$117K |
|
|
MASI
5300
PUT
DELISTED
Masimo
MASI
| $147K | ﹤0.01% |
1,000
+700
| +233% | +$106K |
|
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.