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MKTX in the 13F filings

Marketaxess Holdings Inc · CUSIP 57060D108

Sector · Other financial servicesTheme · Financial services· L3VLUP-defined
Quarter
Q2 2026Q1 2026Q4 2025Q3 2025Q2 2025Q1 2025Q4 2024Q3 2024Q2 2024Q1 2024Q4 2023Q3 2023
Quarter end
30 Jun 2025
the date the book describes
Filed
15 Aug 2025
latest of these filings; the earliest 6 Aug 2025
Managers listing it
19
at least, of 95 tracked, among listed positions
Comparable managers
95
filed both Q1 2025 and Q2 2025; 9 listed it in both
Shares listed
5,379,507
combined, among listed positions
Reported value
$1.2bn
combined, at the quarter end

Among the 95 comparable managers: 13 buyers (opened or added shares) and 9 sellers (trimmed or exited), at least, among listed positions. Their net change in shares is not known from listed positions, because at least one of them lists it in only one of the two quarters.

Managers listing MKTX in Q2 2025

Share of 13F value is the position’s reported value over everything the manager reported that quarter. The share change is against Q1 2025, and only where both filings list the position. A rise in value with no rise in shares is the price, not buying.

19 of 19 holders

ActionFiling
Fidelity (FMR LLC)2,332,146$521munder 0.1%Added+142,23014 Aug 2025 (the filing on sec.gov)
AQR Capital Management LLC758,462$167m0.14%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Millennium Management LLC432,182$97munder 0.1%Trimmed-186,74014 Aug 2025 (the filing on sec.gov)
Two Sigma Investments LP280,089$63m0.11%Trimmed-150,43314 Aug 2025 (the filing on sec.gov)
Arrowstreet Capital LP250,037$56munder 0.1%Addedn.a.13 Aug 2025 (the filing on sec.gov)
Two Sigma Advisers LP243,400$54m0.11%Trimmed-86,00014 Aug 2025 (the filing on sec.gov)
Walleye Capital LLC195,327$44m0.17%Added+35,27513 Aug 2025 (the filing on sec.gov)
Renaissance Technologies LLC190,600$43m0.06%Addedn.a.13 Aug 2025 (the filing on sec.gov)
Baillie Gifford & Co186,689$42munder 0.1%Trimmed-34,5516 Aug 2025 (the filing on sec.gov)
Janus Henderson Group Ltd136,037$30munder 0.1%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Tudor Investment Corp93,154$21munder 0.1%Newnew14 Aug 2025 (the filing on sec.gov)
Holocene Advisors LP76,574$17munder 0.1%Trimmed-174,06814 Aug 2025 (the filing on sec.gov)
Voloridge Investment Management LLC69,026$15m0.06%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Verition Fund Management LLC61,457$14m0.06%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Schonfeld Strategic Advisors LLC32,867$7.3munder 0.1%Trimmed-13,80514 Aug 2025 (the filing on sec.gov)
Brevan Howard Capital Management LP18,725$4.2munder 0.1%Addedn.a.14 Aug 2025 (the filing on sec.gov)
Winton Group Ltd14,508$3.2m0.17%Newnew14 Aug 2025 (the filing on sec.gov)
Moore Capital Management LP5,079$1.1munder 0.1%Added+3,57314 Aug 2025 (the filing on sec.gov)
Caxton Associates LLP3,148$703kunder 0.1%Newnew15 Aug 2025 (the filing on sec.gov)

Largest increases and reductions, by shares

Q1 2025 to Q2 2025, among managers that listed it in both quarters or opened it.

Increases

Reductions

New positions and exits

At least these many: a manager is shown exiting only where its own filing shows the position gone.

New (3)

Exited (3)

Ownership over time

Every quarter on file. A quarter-end value moves with the price as well as with the shares held; buyers and sellers count comparable managers, by shares.
14 in Q3 2024 to 10 in Q2 2026

Tracked managers listing it, at least.

051015202014201620182020202220242026
the quarter shown share split complete books; unmarked quarters rest on listed positionsClick a quarter to open it.
MKTX by quarter
QuarterHoldersReported valueBuyersSellers
Q2 20132$24mn.a.n.a.
Q3 20133$53mn.a.n.a.
Q4 20133$65mn.a.n.a.
Q1 20143$75mn.a.n.a.
Q2 20142$104mn.a.n.a.
Q3 20144$158mn.a.n.a.
Q4 20143$170mn.a.n.a.
Q1 20153$215mn.a.n.a.
Q2 20154$381mn.a.n.a.
Q3 20154$426mn.a.n.a.
Q4 20155$566mn.a.n.a.
Q1 20165$717mn.a.n.a.
Q2 20168$1.1bnn.a.n.a.
Q3 20168$1.1bnn.a.n.a.
Q4 20169$785mn.a.n.a.
Q1 201711$1.3bnn.a.n.a.
Q2 201711$1.6bnn.a.n.a.
Q3 20179$1.5bnn.a.n.a.
Q4 201713$2.4bnn.a.n.a.
Q1 201813$2.7bnn.a.n.a.
Q2 201812$2.4bnn.a.n.a.
Q3 201811$2.1bnn.a.n.a.
Q4 201812$2.5bnn.a.n.a.
Q1 201911$2.7bnn.a.n.a.
Q2 201912$3.4bnn.a.n.a.
Q3 201910$3.2bnn.a.n.a.
Q4 201912$3.3bnn.a.n.a.
Q1 202018$2.5bnn.a.n.a.
Q2 202016$3.2bnn.a.n.a.
Q3 202015$2.7bnn.a.n.a.
Q4 202016$3.4bnn.a.n.a.
Q1 202117$3.4bnn.a.n.a.
Q2 202113$3.6bnn.a.n.a.
Q3 202112$3.1bnn.a.n.a.
Q4 202114$3.2bnn.a.n.a.
Q1 202214$2.3bnn.a.n.a.
Q2 202218$1.6bnn.a.n.a.
Q3 202216$672mn.a.n.a.
Q4 20229$671mn.a.n.a.
Q1 20237$1.1bnn.a.n.a.
Q2 20239$756mn.a.n.a.
Q3 202314$595mn.a.n.a.
Q4 202313$898m85
Q1 20249$353m55
Q2 202414$562m114
Q3 202414$1.0bn95
Q4 202415$1.0bn96
Q1 202513$1.0bn95
Q2 202519$1.2bn139
Q3 202516$670m133
Q4 202514$892m1620
Q1 202613$1.0bn1319
Q2 202610$475m1915

Compare with…

Holders over time, buyers and sellers, and the managers holding both, side by side for up to four stocks.

MKTX and V →MKTX and AXP →MKTX and BAC →Choose a stock to compare with MKTX →

How much of the picture this is

A 13F is a manager’s long US-listed equity book at a quarter end, filed up to 45 days later. It shows no shorts, cash, bonds or performance, and it is never today’s portfolio. Large books are listed to their largest positions, so a manager missing from this table may still hold a small position below that line. These are 95 tracked managers, not the institutional market.

Which funds own MKTX, latest filings →Back to the 13F Explorer →