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 |
Netflix
NFLX
|
+$73.1M |
| 2 |
Western Digital
WDC
|
+$51.8M |
| 3 |
iShares Semiconductor ETF
SOXX
|
+$46M |
| 4 |
Meta Platforms (Facebook)
META
|
+$41.8M |
| 5 |
Alibaba
BABA
|
+$37.1M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
NVIDIA
NVDA
|
+$262M |
| 2 |
Microsoft
MSFT
|
+$194M |
| 3 |
iShares Russell 2000 ETF
IWM
|
+$149M |
| 4 |
Apple
AAPL
|
+$119M |
| 5 |
Amazon
AMZN
|
+$107M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 0.59% |
| 2 | Consumer Discretionary | 0.21% |
| 3 | Healthcare | 0.2% |
| 4 | Industrials | 0.18% |
| 5 | Communication Services | 0.16% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
201
PUT
Coca-Cola
KO
$355B
| $74.6M | 0.04% |
1,067,300
+174,000
| +19% | +$12.1M |
|
202
CALL
ARK Space & Defense Innovation ETF
ARKX
$829M
| $73.2M | 0.04% |
1,217,600
-437,500
| -26% | -$12.8M |
|
203
CALL
Energy Transfer Partners
ET
$70.1B
| $73.2M | 0.04% |
4,438,100
-242,500
| -5% | -$4.04M |
|
204
CALL
American Express
AXP
$238B
| $73M | 0.04% |
197,200
-18,100
| -8% | -$6.48M |
|
205
PUT
Wolfspeed
WOLF
$1.59B
| $72.1M | 0.04% |
4,141,100
-3,631,800
| -47% | -$83.3M |
|
206
CALL
Marvell Technology
MRVL
$192B
| $72.1M | 0.04% |
848,300
-612,100
| -42% | -$53.6M |
|
207
PUT
United Airlines
UAL
$38.5B
| $71.7M | 0.04% |
640,800
+86,300
| +16% | +$8.72M |
|
208
CALL
Bloom Energy
BE
$65.3B
| $71.2M | 0.04% |
819,900
-585,900
| -42% | -$61.6M |
|
209
PUT
PayPal
PYPL
$49.1B
| $71.2M | 0.04% |
1,220,000
-487,800
| -29% | -$31.7M |
|
210
CALL
Starbucks
SBUX
$118B
| $69.3M | 0.04% |
823,500
-171,700
| -17% | -$14.5M |
|
211
PUT
D-Wave Quantum
QBTS
$6.52B
| $69.2M | 0.04% |
2,645,300
+430,200
| +19% | +$12.5M |
|
212
CALL
United Parcel Service
UPS
$99.1B
| $69M | 0.04% |
695,900
-339,800
| -33% | -$31.8M |
|
213
CALL
GameStop
GME
$9.74B
| $68.7M | 0.04% |
5,387,500
+938,900
| +21% | +$21.1M |
|
|
ETHA
214
PUT
iShares Ethereum Trust ETF
ETHA
$5.48B
| $68.5M | 0.04% |
3,055,000
-372,700
| -11% | -$9.75M |
|
215
CALL
Chipotle Mexican Grill
CMG
$42.2B
| $68.4M | 0.04% |
1,848,800
-451,700
| -20% | -$16.3M |
|
216
CALL
Rivian
RIVN
$25.3B
| $68.2M | 0.04% |
3,462,600
-67,500
| -2% | -$1.07M |
|
|
217
PUT
Western Digital
WDC
$194B
| $67.9M | 0.04% |
537,100
-262,600
| -33% | -$39.8M |
|
218
CALL
Procter & Gamble
PG
$350B
| $67.8M | 0.04% |
472,900
-109,500
| -19% | -$16.1M |
|
|
CRCL
219
PUT
Circle Internet Group
CRCL
$16.9B
| $67.1M | 0.04% |
846,700
-147,300
| -15% | -$15.2M |
|
220
PUT
Reddit
RDDT
$32.5B
| $66.3M | 0.04% |
288,500
-458,200
| -61% | -$96.4M |
|
221
PUT
Carnival Corporation Ltd
CCL
$36B
| $66.3M | 0.04% |
2,169,700
-1,395,000
| -39% | -$38.9M |
|
222
PUT
MongoDB
MDB
$24.6B
| $65.8M | 0.04% |
156,700
-96,900
| -38% | -$35.3M |
|
223
CALL
Booking.com
BKNG
$139B
| $65.3M | 0.04% |
305,000
-170,000
| -36% | -$35M |
|
|
OKLO
224
PUT
Oklo
OKLO
$7.9B
| $65.1M | 0.04% |
907,700
-68,900
| -7% | -$7.68M |
|
|
225
Netflix
NFLX
$292B
| $64.8M | 0.04% |
691,029
+678,279
| +5,320% | +$73.1M |
|
Similar funds
Simplex Trading's Q4 2025 Portfolio in Review
As of Q4 2025, Simplex Trading held 10,526 positions worth $177B, down 9% from $195B the previous quarter. Its ten largest holdings account for 49% of the portfolio.
Simplex Trading withdrew a net $23.2B in Q4 2025, closing 2,184 positions and reducing 4,088 holdings. Its most notable exit was iShares Russell 2000 ETF, an estimated $149M position sold in full.
By sector, the portfolio is most concentrated in Technology at 0.59% of assets, down from 0.79% a quarter earlier, followed by Consumer Discretionary and Healthcare.
Against the trend, Simplex Trading opened a new position in Western Digital worth $58.9M.
- Simplex Trading's largest Q4 2025 buy was Western Digital: 341,762 shares worth $58.9M.
- Simplex Trading added most to Netflix in Q4 2025, an estimated $73.1M increase.
- Simplex Trading's biggest Q4 2025 reduction was NVIDIA, cutting an estimated $262M.
- Simplex Trading fully exited iShares Russell 2000 ETF in Q4 2025, selling an estimated $149M.
- Simplex Trading's ten largest holdings make up 49% of its $177B portfolio in Q4 2025.
- Simplex Trading opened 1,476 new positions and closed 2,184 in Q4 2025.
- Simplex Trading's portfolio value fell 9% quarter-over-quarter to $177B.
Based on Simplex Trading's 13F filing for Q4 2025, filed 11 Feb 2026.