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 | |
|---|---|---|---|---|---|---|
5526
CALL
Riley Exploration Permian
REPX
$744M
| $121K | ﹤0.01% |
4,500
+3,400
| +309% | +$92.9K |
|
5527
CALL
Blue Bird Corp
BLBD
$2.35B
| $120K | ﹤0.01% |
2,100
-4,000
| -66% | -$209K |
|
|
DSL
5528
CALL
DoubleLine Income Solutions Fund
DSL
$1.22B
| $120K | ﹤0.01% |
9,800
-4,800
| -33% | -$58.9K |
|
5529
Flywire
FLYW
$1.98B
| $120K | ﹤0.01% |
8,889
-97,950
| -92% | -$1.2M |
|
5530
PUT
iRadimed
IRMD
$1.16B
| $120K | ﹤0.01% |
+1,700
| New | +$113K |
|
5531
CALL
Korea Electric Power
KEP
$15.3B
| $120K | ﹤0.01% |
9,200
+8,200
| +820% | +$112K |
|
|
LQIG
5532
DELISTED
State Street SPDR MarketAxess Investment Grade 400 Corporate Bond ETF
LQIG
| $120K | ﹤0.01% |
+1,240
| New | +$119K |
|
5533
CALL
Timken Company
TKR
$9.56B
| $120K | ﹤0.01% |
1,600
+600
| +60% | +$46.3K |
|
|
CAI
5534
Caris Life Sciences
CAI
$4.43B
| $120K | ﹤0.01% |
3,983
+3,151
| +379% | +$100K |
|
5535
AppFolio
APPF
$6.38B
| $119K | ﹤0.01% |
+434
| New | +$117K |
|
5536
PUT
AudioCodes
AUDC
$244M
| $119K | ﹤0.01% |
12,500
+200
| +2% | +$1.96K |
|
5537
CALL
Heartland Express
HTLD
$948M
| $119K | ﹤0.01% |
14,300
| – | – |
|
|
PPLI
5538
CALL
People Inc
PPLI
$3.09B
| $119K | ﹤0.01% |
3,500
-200
| -5% | -$7.46K |
|
|
RPC
5539
CALL
Ridgepost Capital
RPC
$949M
| $119K | ﹤0.01% |
11,000
+9,100
| +479% | +$108K |
|
5540
Regenxbio
RGNX
$620M
| $119K | ﹤0.01% |
+12,377
| New | +$109K |
|
5541
VSE Corp
VSEC
$5.45B
| $119K | ﹤0.01% |
717
+515
| +255% | +$78.5K |
|
5542
AXT Inc
AXTI
$3.95B
| $118K | ﹤0.01% |
26,310
+14,381
| +121% | +$41.1K |
|
5543
PUT
Capital Southwest
CSWC
$1.47B
| $118K | ﹤0.01% |
5,400
-3,100
| -36% | -$70.6K |
|
5544
Golar LNG
GLNG
$5B
| $118K | ﹤0.01% |
2,933
-43,169
| -94% | -$1.78M |
|
5545
PUT
Disc Medicine
IRON
$2.96B
| $118K | ﹤0.01% |
1,800
+1,300
| +260% | +$77.3K |
|
5546
Microvast
MVST
$269M
| $118K | ﹤0.01% |
30,889
+1,009
| +3% | +$3.15K |
|
5547
CALL
Envista
NVST
$4.44B
| $118K | ﹤0.01% |
5,800
+900
| +18% | +$18.5K |
|
5548
PUT
SFL Corp
SFL
$1.64B
| $118K | ﹤0.01% |
15,800
+1,000
| +7% | +$8.61K |
|
5549
PUT
TransAlta
TAC
$3.95B
| $118K | ﹤0.01% |
+8,700
| New | +$107K |
|
5550
PUT
Tonix Pharmaceuticals
TNXP
$160M
| $118K | ﹤0.01% |
+4,900
| New | +$182K |
|
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.