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 | |
|---|---|---|---|---|---|---|
5001
PUT
Martin Marietta Materials
MLM
$32.4B
| $189K | ﹤0.01% |
300
-5,200
| -95% | -$3.1M |
|
5002
PUT
Quantum-Si Incorporated
QSI
$157M
| $189K | ﹤0.01% |
134,200
-10,000
| -7% | -$14.5K |
|
|
SOGP
5003
Sound Group
SOGP
$49.9M
| $189K | ﹤0.01% |
10,052
+6,205
| +161% | +$68.4K |
|
5004
PUT
Zedge
ZDGE
$38.8M
| $189K | ﹤0.01% |
+65,100
| New | +$231K |
|
5005
Zurn Elkay Water Solutions
ZWS
$8.31B
| $189K | ﹤0.01% |
4,032
+4,018
| +28,700% | +$173K |
|
|
IMSR
5006
CALL
Terrestrial Energy
IMSR
$553M
| $189K | ﹤0.01% |
+114,600
| New | +$1.36M |
|
|
UXRP
5007
Proshares Ultra XRP ETF
UXRP
$28.2M
| $189K | ﹤0.01% |
+1,322
| New | +$243K |
|
5008
Alta Equipment Group
ALTG
$197M
| $188K | ﹤0.01% |
26,009
+9,222
| +55% | +$71.7K |
|
5009
CALL
Donaldson
DCI
$10.7B
| $188K | ﹤0.01% |
2,300
-27,300
| -92% | -$2.06M |
|
5010
G-III Apparel Group
GIII
$1.55B
| $188K | ﹤0.01% |
7,073
-6,622
| -48% | -$168K |
|
5011
Nexstar Media Group
NXST
$5.88B
| $188K | ﹤0.01% |
+955
| New | +$187K |
|
5012
ProKidney
PROK
$324M
| $188K | ﹤0.01% |
+77,818
| New | +$207K |
|
|
SOFX
5013
Defiance Daily Target 2X Long SOFI ETF
SOFX
$71M
| $188K | ﹤0.01% |
+4,848
| New | +$161K |
|
5014
Dyne Therapeutics
DYN
$4.8B
| $187K | ﹤0.01% |
14,838
+1,591
| +12% | +$18.1K |
|
|
EU
5015
CALL
enCore Energy
EU
$219M
| $187K | ﹤0.01% |
58,400
+14,100
| +32% | +$38K |
|
5016
CALL
FingerMotion
FNGR
$14.5M
| $187K | ﹤0.01% |
118,800
+24,100
| +25% | +$39.9K |
|
5017
PUT
Macerich
MAC
$7.22B
| $187K | ﹤0.01% |
10,300
-1,000
| -9% | -$17.3K |
|
5018
Invesco S&P 500 Equal Weight Energy ETF
RSPG
$555M
| $187K | ﹤0.01% |
2,356
-143
| -6% | -$11K |
|
5019
iShares TIPS Bond ETF
TIP
$14.5B
| $187K | ﹤0.01% |
1,688
+1,097
| +186% | +$121K |
|
|
STEX
5020
Streamex Corp
STEX
$78.1M
| $186K | ﹤0.01% |
+32,436
| New | +$177K |
|
5021
PUT
Cemex
CX
$17.2B
| $186K | ﹤0.01% |
20,700
+12,600
| +156% | +$108K |
|
|
MURA
5022
DELISTED
Mural Oncology
MURA
| $186K | ﹤0.01% |
90,256
+26,957
| +43% | +$57.9K |
|
|
ODP
5023
PUT
DELISTED
ODP
ODP
| $186K | ﹤0.01% |
6,700
+6,500
| +3,250% | +$133K |
|
5024
CALL
SandRidge Energy
SD
$501M
| $186K | ﹤0.01% |
16,500
-12,400
| -43% | -$137K |
|
|
SVC
5025
CALL
Service Properties Trust
SVC
$1.04B
| $186K | ﹤0.01% |
13,800
+13,680
| +11,400% | +$185K |
|
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.