Skip to main content
Livermore
Livermore
ZHEN

Marketaxess Holdings Inc

MKTX
Exchange
Nasdaq
Industry
Security Brokers, Dealers & Flotation Companies
SEC CIK
0001278021

In the last 90 days, Marketaxess Holdings Inc insiders filed 0 open-market purchases and 4 sales; 397 institutions reported holding it in 13F filings for Q2 2026, worth $4.44B in total; no superinvestor holds it.

Holders of 5% or more of MKTX

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Marketaxess Holdings Inc, largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of MKTX
HolderLatest formStakeChangeFirst filedLatest filingFiling
BlackRock, Inc.13G/A10.90%4.03M shares+1.00 ppfrom 9.90%Apr 17, 20254 filingsFeb 6, 2026SEC
Primecap Management Co13G/A9.86%3.50M shares+1.32 ppfrom 8.54%Nov 13, 20253 filingsAug 6, 2026SEC
North Reef Capital Management LP13G/A9.55%3.40M shares+4.28 ppfrom 5.27%May 15, 20262 filingsAug 14, 2026SEC
Vanguard Portfolio Management LLC13G6.09%2.17M sharesNewApr 29, 20261 filingApr 29, 2026SEC
AQR Capital Management LLC13G/A5.59%1.99M shares−1.29 ppfrom 6.88%Feb 13, 20262 filingsAug 13, 2026SEC
Vanguard Capital Management LLC13G5.32%1.89M sharesNewApr 30, 20261 filingApr 30, 2026SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

19 Schedule 13D and 13G filings on Marketaxess Holdings Inc, newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on MKTX
Filed (ET)FilerFormStakeChangeEvent dateFiling
Aug 14, 20264:00 PM ETNorth Reef Capital Management LPand 2 others13G/A9.55%3.40M shares+4.28 ppfrom 5.27%Jun 30, 2026SEC
Aug 13, 202611:13 AM ETAQR Capital Management LLCand 1 other13G/A5.59%1.99M shares−1.29 ppfrom 6.88%Jun 30, 2026SEC
Aug 6, 20264:14 PM ETPrimecap Management Co13G/A9.86%3.50M shares+1.32 ppfrom 8.54%Jun 30, 2026SEC
May 15, 20262:00 PM ETNorth Reef Capital Management LPand 2 others13G5.27%1.88M sharesNewMar 31, 2026SEC
May 6, 202611:30 AM ETFMR LLCand 1 other13G/A4.20%1.50M shares−1.90 ppfrom 6.10%Below 5%Mar 31, 2026SEC
Apr 30, 202611:45 AM ETVanguard Capital Management LLC13G5.32%1.89M sharesNewMar 31, 2026SEC
Apr 29, 20262:14 PM ETVanguard Portfolio Management LLC13G6.09%2.17M sharesNewMar 31, 2026SEC
Mar 27, 202610:30 AM ETVanguard Group Inc13G/A0.00%0 shares−10.31 ppfrom 10.31%Below 5%Mar 13, 2026SEC
Feb 13, 20269:17 AM ETAQR Capital Management LLCand 1 other13G6.88%2.56M sharesNewDec 31, 2025SEC
Feb 11, 202612:56 PM ETPrimecap Management Co13G/A8.54%3.18M shares+2.57 ppfrom 5.97%Dec 31, 2025SEC
Feb 6, 202612:08 PM ETBlackRock, Inc.13G/A10.90%4.03M shares+1.00 ppfrom 9.90%Jan 31, 2026SEC
Jan 21, 202612:30 PM ETBlackRock, Inc.13G9.90%3.68M shares+5.70 ppfrom 4.20%Dec 31, 2025SEC
Nov 14, 202512:18 PM ETT. Rowe Price Investment Management, Inc.13G/A3.70%1.37M shares–Below 5%Sep 30, 2025SEC
Nov 13, 20258:32 PM ETPrimecap Management Co13G5.97%2.23M sharesNewSep 30, 2025SEC
Oct 31, 202511:04 AM ETVanguard Group Inc13G/A10.31%3.85M shares–Sep 30, 2025SEC
Oct 17, 20256:13 PM ETBlackRock, Inc.13G/A4.20%1.57M shares−2.40 ppfrom 6.60%Below 5%Sep 30, 2025SEC
Aug 6, 202512:06 PM ETFMR LLCand 1 other13G/A6.10%2.30M shares–Jun 30, 2025SEC
Apr 17, 20259:35 AM ETBlackRock, Inc.13G/A6.60%2.48M shares–Mar 31, 2025SEC
Feb 14, 20254:14 PM ETGuardian Capital LPand 1 other13G/A4.75%1.79M shares–Below 5%Dec 31, 2024SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell Marketaxess Holdings Inc shares.

No Form 144 notices for Marketaxess Holdings Inc are on file.