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 | |
|---|---|---|---|---|---|---|
2676
CALL
Corcept Therapeutics
CORT
$10.2B
| $943K | ﹤0.01% |
27,100
-1,100
| -4% | -$86.4K |
|
2677
The RealReal
REAL
$1.34B
| $943K | ﹤0.01% |
59,738
+16,253
| +37% | +$212K |
|
2678
Kyndryl
KD
$2.66B
| $942K | ﹤0.01% |
35,484
-18,798
| -35% | -$510K |
|
2679
CALL
EPAM Systems
EPAM
$4.69B
| $942K | ﹤0.01% |
4,600
+2,000
| +77% | +$357K |
|
2680
PUT
Cooper-Standard Automotive
CPS
$504M
| $942K | ﹤0.01% |
28,700
-12,600
| -31% | -$410K |
|
2681
NextDecade
NEXT
$1.85B
| $940K | ﹤0.01% |
178,436
+162,335
| +1,008% | +$968K |
|
|
TSSI
2682
CALL
TSS Inc
TSSI
$272M
| $940K | ﹤0.01% |
133,000
+18,300
| +16% | +$236K |
|
2683
PUT
TETRA Technologies
TTI
$1.23B
| $940K | ﹤0.01% |
100,300
+69,600
| +227% | +$537K |
|
2684
iShares 3-7 Year Treasury Bond ETF
IEI
$18.1B
| $939K | ﹤0.01% |
7,865
-7,538
| -49% | -$902K |
|
2685
Aurinia Pharmaceuticals
AUPH
$1.97B
| $938K | ﹤0.01% |
+58,793
| New | +$833K |
|
|
BORR
2686
CALL
Borr Drilling
BORR
$1.31B
| $937K | ﹤0.01% |
232,400
+72,700
| +46% | +$241K |
|
2687
CALL
Chord Energy
CHRD
$7.79B
| $936K | ﹤0.01% |
10,100
-3,800
| -27% | -$352K |
|
2688
Linde
LIN
$237B
| $936K | ﹤0.01% |
+2,195
| New | +$940K |
|
2689
PUT
Wendy's
WEN
$1.33B
| $935K | ﹤0.01% |
112,300
-242,800
| -68% | -$2.1M |
|
|
FLY
2690
PUT
Firefly Aerospace
FLY
$3.23B
| $935K | ﹤0.01% |
41,800
-24,300
| -37% | -$562K |
|
2691
PUT
Jazz Pharmaceuticals
JAZZ
$15.9B
| $935K | ﹤0.01% |
5,500
+4,500
| +450% | +$690K |
|
2692
PUT
Roper Technologies
ROP
$36.3B
| $935K | ﹤0.01% |
2,100
+1,100
| +110% | +$509K |
|
2693
PUT
Tenaris
TS
$29.1B
| $930K | ﹤0.01% |
24,200
+13,300
| +122% | +$513K |
|
2694
CALL
ClearShares Piton Intermediate Fixed Income ETF
PIFI
$97.5M
| $930K | ﹤0.01% |
25,100
-102,900
| -80% | -$9.81M |
|
2695
Cencora
COR
$60.3B
| $928K | ﹤0.01% |
+2,748
| New | +$937K |
|
2696
CALL
SM Energy
SM
$7.96B
| $928K | ﹤0.01% |
49,600
+11,900
| +32% | +$241K |
|
|
LINE
2697
PUT
Lineage Inc
LINE
$9.43B
| $928K | ﹤0.01% |
26,500
+24,000
| +960% | +$887K |
|
2698
Nektar Therapeutics
NKTR
$2.39B
| $927K | ﹤0.01% |
21,936
-54,514
| -71% | -$3.05M |
|
2699
PUT
Replimune Group
REPL
$814M
| $927K | ﹤0.01% |
95,400
-227,900
| -70% | -$1.94M |
|
2700
PUT
Iovance Biotherapeutics
IOVA
$2.23B
| $927K | ﹤0.01% |
339,600
+89,200
| +36% | +$206K |
|
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.