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 | |
|---|---|---|---|---|---|---|
4126
CALL
Installed Building Products
IBP
$6.37B
| $394K | ﹤0.01% |
1,600
-300
| -16% | -$71.2K |
|
|
MESO
4127
PUT
Mesoblast
MESO
$1.87B
| $394K | ﹤0.01% |
24,500
-13,100
| -35% | -$192K |
|
|
MLNK
4128
CALL
DELISTED
MeridianLink
MLNK
| $394K | ﹤0.01% |
19,800
+18,900
| +2,100% | +$347K |
|
4129
Neuronetics
STIM
$137M
| $394K | ﹤0.01% |
144,490
+108,297
| +299% | +$385K |
|
4130
Repligen
RGEN
$6.93B
| $393K | ﹤0.01% |
+2,943
| New | +$357K |
|
4131
PUT
Worthington Enterprises
WOR
$2.78B
| $393K | ﹤0.01% |
7,100
+6,000
| +545% | +$378K |
|
4132
PUT
Yext
YEXT
$577M
| $393K | ﹤0.01% |
46,200
+29,600
| +178% | +$251K |
|
4133
CALL
EPAM Systems
EPAM
$5.67B
| $392K | ﹤0.01% |
2,600
-500
| -16% | -$82.1K |
|
4134
PUT
Lightspeed Commerce
LSPD
$1.44B
| $392K | ﹤0.01% |
34,000
+3,200
| +10% | +$39.1K |
|
4135
PUT
Neonode
NEON
$12.7M
| $392K | ﹤0.01% |
112,400
+95,900
| +581% | +$1.77M |
|
|
TTAN
4136
ServiceTitan Inc
TTAN
$8.15B
| $392K | ﹤0.01% |
+3,890
| New | +$427K |
|
4137
CALL
Cato Corp
CATO
$66.5M
| $391K | ﹤0.01% |
+92,900
| New | +$327K |
|
4138
PACCAR
PCAR
$72.3B
| $391K | ﹤0.01% |
3,984
-7,849
| -66% | -$774K |
|
4139
ProShares Short VIX Short-Term Futures ETF
SVXY
$225M
| $391K | ﹤0.01% |
7,683
-8,674
| -53% | -$408K |
|
4140
PUT
ArriVent BioPharma
AVBP
$1.41B
| $391K | ﹤0.01% |
+21,200
| New | +$417K |
|
|
ODVWW
4141
CALL
DELISTED
Osisko Development Corp. Warrant
ODVWW
| $391K | ﹤0.01% |
115,600
-40,800
| -26% | -$138K |
|
4142
PUT
ADT
ADT
$5.46B
| $390K | ﹤0.01% |
44,800
+20,900
| +87% | +$179K |
|
4143
Kilroy Realty
KRC
$4.64B
| $390K | ﹤0.01% |
9,232
+4,700
| +104% | +$185K |
|
4144
CALL
Virtu Financial
VIRT
$5.12B
| $390K | ﹤0.01% |
11,000
-4,500
| -29% | -$185K |
|
|
AWTM
4145
CALL
DELISTED
AWTM Ultra-Short Duration Enhanced Income ETF
AWTM
| $390K | ﹤0.01% |
15,700
+14,500
| +1,208% | +$360K |
|
4146
PUT
Global E Online
GLBE
$6.71B
| $389K | ﹤0.01% |
10,900
-15,700
| -59% | -$536K |
|
4147
PUT
Tenaris
TS
$28.4B
| $389K | ﹤0.01% |
10,900
-18,600
| -63% | -$675K |
|
4148
CALL
Allot
ALLT
$370M
| $388K | ﹤0.01% |
36,700
+18,800
| +105% | +$160K |
|
|
HTT
4149
CALL
High Templar Tech Ltd
HTT
$377M
| $388K | ﹤0.01% |
90,900
-4,600
| -5% | -$18.4K |
|
4150
CALL
LendingTree
TREE
$570M
| $388K | ﹤0.01% |
6,000
+1,900
| +46% | +$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.