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 | |
|---|---|---|---|---|---|---|
3976
PUT
Atea Pharmaceuticals
AVIR
$361M
| $441K | ﹤0.01% |
+152,300
| New | +$520K |
|
|
DRD
3977
CALL
DRDGold
DRD
$1.79B
| $441K | ﹤0.01% |
16,000
+2,000
| +14% | +$35.8K |
|
3978
CALL
Vertical Aerospace
EVTL
$172M
| $441K | ﹤0.01% |
+85,100
| New | +$473K |
|
3979
Alkermes
ALKS
$8.47B
| $440K | ﹤0.01% |
+14,667
| New | +$414K |
|
3980
Korea Electric Power
KEP
$14.9B
| $440K | ﹤0.01% |
33,746
-44,248
| -57% | -$603K |
|
3981
CALL
WisdomTree US Total Dividend Fund
DTD
$1.66B
| $439K | ﹤0.01% |
3,700
+1,600
| +76% | +$131K |
|
3982
PUT
Global Net Lease
GNL
$1.86B
| $439K | ﹤0.01% |
54,100
+36,500
| +207% | +$279K |
|
3983
Essential Utilities
WTRG
$11.5B
| $439K | ﹤0.01% |
11,023
-6,272
| -36% | -$239K |
|
|
NAGE
3984
CALL
Niagen Bioscience
NAGE
$262M
| $438K | ﹤0.01% |
47,000
+34,500
| +276% | +$348K |
|
3985
CALL
Group 1 Automotive
GPI
$4.17B
| $437K | ﹤0.01% |
1,000
-500
| -33% | -$224K |
|
3986
CALL
IES Holdings
IESC
$10.8B
| $437K | ﹤0.01% |
1,100
-400
| -27% | -$138K |
|
|
3987
PUT
IES Holdings
IESC
$10.8B
| $437K | ﹤0.01% |
1,100
-4,000
| -78% | -$1.38M |
|
3988
PUT
MiMedx Group
MDXG
$649M
| $437K | ﹤0.01% |
62,700
+34,300
| +121% | +$238K |
|
3989
Ambarella
AMBA
$3.03B
| $436K | ﹤0.01% |
5,290
-813
| -13% | -$59K |
|
3990
CALL
Cognyte Software
CGNT
$657M
| $436K | ﹤0.01% |
52,000
+29,700
| +133% | +$263K |
|
3991
CALL
Navios Maritime Partners
NMM
$2.25B
| $436K | ﹤0.01% |
9,700
-22,100
| -69% | -$978K |
|
3992
Weyerhaeuser
WY
$17.7B
| $436K | ﹤0.01% |
17,623
-2,306
| -12% | -$59K |
|
3993
CALL
Dentsply Sirona
XRAY
$2.7B
| $436K | ﹤0.01% |
34,400
-14,800
| -30% | -$215K |
|
3994
PUT
Critical Metals Corp
CRML
$831M
| $436K | ﹤0.01% |
+70,100
| New | +$359K |
|
3995
PUT
Fastly Inc
FSLY
$3.26B
| $435K | ﹤0.01% |
50,900
-20,400
| -29% | -$151K |
|
3996
CALL
Laser Photonics
LASE
$52.2M
| $435K | ﹤0.01% |
101,000
+100,100
| +11,122% | +$323K |
|
3997
PUT
Phreesia
PHR
$671M
| $435K | ﹤0.01% |
18,500
+3,500
| +23% | +$95.2K |
|
3998
CALL
TransUnion
TRU
$16.1B
| $435K | ﹤0.01% |
5,200
-37,700
| -88% | -$3.42M |
|
|
DDL
3999
CALL
Dingdong
DDL
$527M
| $433K | ﹤0.01% |
209,400
-60,800
| -23% | -$132K |
|
4000
Mettler-Toledo International
MTD
$28.1B
| $433K | ﹤0.01% |
353
-483
| -58% | -$605K |
|
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.