Simplex Trading
MKTX icon

Simplex Trading’s MarketAxess Holdings MKTX Stock Holding History

Simplex Trading’s Portfolio MKTX Stock Details MKTX Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$1.68M Buy
10,200
+8,600
+538% +$1.51M ﹤0.01% 1985
2025
Q4 		$290K Sell
1,600
-500
-24% -$85.3K ﹤0.01% 3854
2025
Q3 		$365K Sell
2,100
-5,000
-70% -$978K ﹤0.01% 4219
2025
Q2 		$1.58M Sell
7,100
-16,500
-70% -$3.63M ﹤0.01% 2314
2025
Q1 		$5.11M Buy
23,600
+14,800
+168% +$3.11M ﹤0.01% 1292
2024
Q4 		$1.99M Buy
8,800
+8,200
+1,367% +$2.16M ﹤0.01% 2195
2024
Q3 		$153K Sell
600
-9,500
-94% -$2.23M ﹤0.01% 4788
2024
Q2 		$2.02M Buy
10,100
+2,200
+28% +$454K ﹤0.01% 2191
2024
Q1 		$1.73M Sell
7,900
-5,300
-40% -$1.25M ﹤0.01% 2556
2023
Q4 		$3.87M Sell
13,200
-15,400
-54% -$3.72M ﹤0.01% 1780
2023
Q3 		$6.11M Buy
28,600
+25,400
+794% +$6.16M ﹤0.01% 1206
2023
Q2 		$836K Buy
3,200
+800
+33% +$239K ﹤0.01% 2774
2023
Q1 		$939K Buy
2,400
+1,600
+200% +$567K ﹤0.01% 2654
2022
Q4 		$223K Sell
800
-3,000
-79% -$772K ﹤0.01% 4102
2022
Q3 		$845K Sell
3,800
-1,700
-31% -$436K ﹤0.01% 2850
2022
Q2 		$1.41M Buy
5,500
+3,700
+206% +$1.01M ﹤0.01% 2238
2022
Q1 		$612K Buy
1,800
+400
+29% +$145K ﹤0.01% 3580
2021
Q4 		$575K Sell
1,400
-1,800
-56% -$710K ﹤0.01% 3612
2021
Q3 		$1.49M Hold
3,200
– – ﹤0.01% 2552
2021
Q2 		$1.48M Buy
3,200
+3,174
+12,208% +$1.51M ﹤0.01% 2578
2021
Q1 		$1.29M Buy
26
+8
+44% +$4.27K ﹤0.01% 2116
2020
Q4 		$1.03M Sell
18
-22
-55% -$12K ﹤0.01% 2532
2020
Q3 		$1.93M Sell
40
-54
-57% -$26.7K ﹤0.01% 1563
2020
Q2 		$4.71M Sell
94
-26
-22% -$12.1K 0.01% 889
2020
Q1 		$3.99M Buy
120
+76
+173% +$26.5K 0.01% 816
2019
Q4 		$1.67M Buy
44
+15
+52% +$5.5K ﹤0.01% 1638
2019
Q3 		$949K Buy
29
+25
+625% +$8.95K ﹤0.01% 1974
2019
Q2 		$128K Buy
4
+2
+100% +$578 ﹤0.01% 3930
2019
Q1 		$49K Buy
+2
New +$453 ﹤0.01% 5029
2018
Q4 		– Sell
-9
Closed -$160K – 7501
2018
Q3 		$160K Sell
9
-2
-18% -$384 ﹤0.01% 3908
2018
Q2 		$217K Buy
11
+10
+1,000% +$2.07K ﹤0.01% 3384
2018
Q1 		$1K Sell
1
-1
-50% -$206 ﹤0.01% 5692
2017
Q4 		$2K Buy
+2
New +$377 ﹤0.01% 5217
2017
Q2 		– Sell
-10
Closed -$38K – 6515
2017
Q1 		$38K Sell
10
-62
-86% -$11.2K ﹤0.01% 2620
2016
Q4 		$18K Sell
72
-12
-14% -$1.91K ﹤0.01% 3130
2016
Q3 		$30K Buy
84
+74
+740% +$12K ﹤0.01% 2569
2016
Q2 		$15K Buy
+10
New +$1.33K ﹤0.01% 3167
2015
Q3 		– Sell
-2
Closed -$1K – 5917
2015
Q2 		$1K Buy
+2
New +$176 ﹤0.01% 4717

Other funds holding MKTX

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Primecap Management
Primecap Management Pasadena, California $127B AUM 44.11% 1-Year Est. Return
AQR Capital Management
AQR Capital Management Greenwich, Connecticut $218B AUM 29.41% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
NRCM
North Reef Capital Management Laguna Beach, California $2.91B AUM 11.03% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
VanEck Associates
VanEck Associates New York $133B AUM 72.99% 1-Year Est. Return
Millennium Management
Millennium Management New York $240B AUM 35.51% 1-Year Est. Return

Simplex Trading's MKTX Position: Q1 2026 in Review

Simplex Trading sold out of MarketAxess Holdings (MKTX) in Q1 2026, closing a stake of 259 shares — an estimated $45.4K sold.

Simplex Trading first reported a position in MKTX in Q3 2015 and held it in 28 quarters. The position peaked at $2.23M in Q3 2019. 447 funds tracked by Wall St. Rank hold MKTX as of Q1 2026.

  • Simplex Trading reported no remaining MarketAxess Holdings position as of Q1 2026 after selling out during the quarter.
  • Simplex Trading sold 259 MarketAxess Holdings shares in Q1 2026, an estimated $45.4K.
  • Simplex Trading first reported a position in MarketAxess Holdings in Q3 2015 and held it in 28 quarters.
  • Simplex Trading's MarketAxess Holdings position peaked at $2.23M in Q3 2019.
  • 447 funds tracked by Wall St. Rank held MarketAxess Holdings as of Q1 2026.

Based on Simplex Trading's 13F filing for Q1 2026, filed 14 May 2026.