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 | |
|---|---|---|---|---|---|---|
4626
Natera
NTRA
$36.4B
| $263K | ﹤0.01% |
+1,638
| New | +$259K |
|
4627
Toro Company
TTC
$8.79B
| $263K | ﹤0.01% |
3,460
+3,243
| +1,494% | +$249K |
|
4628
CALL
Alpha Metallurgical Resources
AMR
$1.77B
| $262K | ﹤0.01% |
1,600
-3,300
| -67% | -$457K |
|
4629
CALL
Icon
ICLR
$13.7B
| $262K | ﹤0.01% |
1,500
+400
| +36% | +$66.9K |
|
4630
CALL
Supernus Pharmaceuticals
SUPN
$2.7B
| $262K | ﹤0.01% |
5,500
+4,900
| +817% | +$197K |
|
|
TEN
4631
CALL
Tsakos Energy Navigation Ltd
TEN
$1.19B
| $262K | ﹤0.01% |
11,800
-25,200
| -68% | -$529K |
|
4632
CALL
Invesco Mortgage Capital
IVR
$759M
| $261K | ﹤0.01% |
34,600
+5,200
| +18% | +$39.7K |
|
4633
SFL Corp
SFL
$1.61B
| $261K | ﹤0.01% |
+34,720
| New | +$299K |
|
4634
CALL
Tyler Technologies
TYL
$13.7B
| $261K | ﹤0.01% |
500
-200
| -29% | -$112K |
|
|
SY
4635
CALL
So-Young International
SY
$195M
| $260K | ﹤0.01% |
67,200
+66,000
| +5,500% | +$281K |
|
4636
PUT
Sixth Street Specialty
TSLX
$1.67B
| $260K | ﹤0.01% |
11,400
+11,300
| +11,300% | +$272K |
|
4637
PUT
Littelfuse
LFUS
$10.4B
| $259K | ﹤0.01% |
+1,000
| New | +$250K |
|
4638
CALL
Atlas Lithium Corp
ATLX
$75.5M
| $258K | ﹤0.01% |
54,300
+40,100
| +282% | +$198K |
|
4639
AptarGroup
ATR
$8.69B
| $258K | ﹤0.01% |
1,934
+847
| +78% | +$122K |
|
4640
BTCS Inc
BTCS
$49.3M
| $258K | ﹤0.01% |
+53,427
| New | +$244K |
|
4641
CALL
Pembina Pipeline
PBA
$29.3B
| $258K | ﹤0.01% |
6,400
-2,600
| -29% | -$98.1K |
|
4642
CALL
Perion Network
PERI
$380M
| $258K | ﹤0.01% |
26,900
-17,000
| -39% | -$170K |
|
4643
Brookfield Infrastructure Partners
BIP
$19.6B
| $257K | ﹤0.01% |
+7,821
| New | +$246K |
|
4644
PUT
BuzzFeed
BZFD
$99M
| $257K | ﹤0.01% |
151,400
-88,300
| -37% | -$180K |
|
4645
Americold
COLD
$4.21B
| $257K | ﹤0.01% |
+21,034
| New | +$313K |
|
4646
CALL
First Industrial Realty Trust
FR
$8.66B
| $257K | ﹤0.01% |
5,000
-9,900
| -66% | -$497K |
|
4647
PUT
Helen of Troy
HELE
$656M
| $257K | ﹤0.01% |
10,200
+1,100
| +12% | +$26.6K |
|
4648
OSI Systems
OSIS
$3.53B
| $257K | ﹤0.01% |
+1,035
| New | +$236K |
|
4649
Sana Biotechnology
SANA
$882M
| $257K | ﹤0.01% |
72,423
+49,741
| +219% | +$180K |
|
4650
Seanergy Maritime Holdings
SHIP
$349M
| $257K | ﹤0.01% |
31,233
+14,533
| +87% | +$110K |
|
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.