Twenty-One of 147: Bill Nygren - Oakmark Funds Is 53.6% of the Superinvestors' June-Quarter Merck Stake. Its Insiders Have Bought Twice.

GetCoattail Research — The Filing Tape #131. Merck has been one of the most-watched stocks on a major stock screen this month, and the filings describe breadth without momentum at the top: 21 of the 147 superinvestors hold the stock — 19 at June 30, 2026, totalling 22,519,230 shares with Bill Nygren - Oakmark Funds at 53.6% of that stake, plus two early third-quarter filers — the verified June cohort grew just 0.4% in a quarter when the full market added 17.29% more shares, insiders have recorded exactly two purchases in the entire parsed record (neither by an officer) against 39 sales, and short interest has risen in each of the last two settlements to 1.40% of the share count.

The Hype

Merck's attention this week is a screen story. The stock is one of the names Zacks.com singled out as most watched by its visitors lately — the subject of an October 15, 2026 Zacks trending-stock note asking what to know beyond why Merck is trending. Zacks Our price file shows a stock that has been climbing for a year: it rose 6.8% in the second quarter, from $120.29 on March 31 to $128.50 on June 30, then added a further 12.3% to close at $144.30 on October 2 — up 37.1% year to date and 61.2% above its close a year earlier, though 7.8% below the 252-session closing high of $156.45 set on August 25, 2026. A top-five trending slot on a stock up 61.2% in a year: the question the filings can answer is who was actually holding it at the June snapshot, and whether the tracked money added while the price ran.

The Tape

For Merck — the one hundred and thirty-first Filing Tape audit — the tape shows a 21-name tracked register split across two period-ends, a June cohort that stood still (+0.4% verified) while the broad market added a sixth more shares, an insider record with two purchases ever — both older than a year, neither by an officer — against 39 sales, a single House purchase, a three-filing passive 5% register headed by a 10.02% print from February 2025, and a borrow that has turned up in the last two settlements.

Lens 1 — the superinvestors: 21 holders split by period, the June top one at 53.6%, and a verified cohort up 0.4%. We track 149 managers whose 13F portfolios we collect from SEC EDGAR — 147 are in the collection: 144 at a June 30 period-end and 3 early filers at September 30, two of them holding this name — and the register for the common stock (CUSIP 58933Y105) splits across both period-ends. At June 30, 2026, 19 holders total 22,519,230 shares worth $2,897,256,403, long only, with no option rows: 8 labelled INCREASED, 5 UNCHANGED and 6 DECREASED, with no new holder and no exit. Bill Nygren - Oakmark Funds is the largest holder: 12,073,109 shares worth $1,551,394,499 — 53.6% of the June stake — at a 2.06% portfolio weight, labelled DECREASED -2.4% (filed August 14, 2026). The second holder, Thornburg Investment Management, holds 3,787,976 shares (16.8%, at a 4.66% weight, labelled INCREASED +1.6%), so the top two hold 70.4% — 15,861,085 shares — between them. The rest of the June register runs Mondrian Investment Partners (1,473,945 shares, at a 2.92% weight), DJE Kapital (1,431,324 shares, at a 3.53% weight), Sarah Ketterer - Causeway Capital Management (954,932 shares), OrbiMed Advisors (663,400 shares), Atalanta Sosnoff Capital (642,053 shares, labelled INCREASED +112.5% from a 302,127-share base), Samlyn Capital (565,755 shares, labelled DECREASED -22.1%), Kahn Brothers Group (218,182 shares, at a 4.43% weight), Saturna Capital (197,643 shares), Prem Watsa - Fairfax Financial Holdings (172,900 shares), Dodge & Cox Funds (135,750 shares), GQG Partners (53,092 shares), Mairs & Power Funds (51,519 shares), Christopher Bloomstran - Semper Augustus (44,633 shares), ACR Alpine Capital Research (41,146 shares), Edgewood Management (7,718 shares), Richard Pzena - Pzena Investment Management (2,511 shares) and Thomas Russo - Gardner Russo & Quinn (1,642 shares, -23.3%). The change verifies row by row for all 19 continuing holders under two register methods that agree exactly (methodology): those 19 held 22,422,956 shares at March 31 and 22,519,230 at June 30 (+96,274 shares, +0.4%). The two remaining holders sit on the later clock: Sarasin & Partners reports 711,274 shares worth $103,355,227 at September 30, 2026 (filed October 13, 2026, at a 1.16% weight), labelled DECREASED -3.4% — a second-to-third-quarter change that reproduces exactly against its own second-quarter register row of 736,662 shares — and David Katz - Matrix Asset Advisors reports 1,621 shares worth $235,548, labelled DECREASED -3.0%, which reproduces against the 1,671-share register row the full-register reconciliation leaves for it (methodology). Together the two early filers are 712,895 shares, 3.1% of the 21-holder collection total of 23,232,125 shares. Seventeen of the 19 June rows imply exactly $128.50, the June 30 close (Fairfax implies $128.39, Russo $128.51 and DJE Kapital $130.98); both September rows imply exactly $145.31, the September 30 close. 13F figures are as of June 30, 2026, except the early filers noted, published up to 45 days later.

Lens 2 — institutions: 87 more filers, and a sixth more shares. At June 30, 2026, 3,793 institutions reported positions, up 87 from 3,706 at March 31 (+2.35%); 3,779 are long. Reported shares rose 17.29%, from 1,670,054,736 to 1,958,782,160 (+288,727,424 shares), and reported value rose 26.51% to $248,892,451,511, labelled "reported" because the aggregate includes option rows (methodology), in a quarter when the price itself rose 6.8%. Flow counts agree: 2,118 entered, 2,031 exited, net +87. The by-ticker row aggregates two CUSIPs: the common stock (58933Y105: 3,788 filers, 1,958,408,042 shares) and a legacy CUSIP (589331107: 6 filers, 374,118 shares — 0.02% of the share count); share and value totals cross-check exactly against the by-CUSIP fixtures (methodology). The reported value implies $127.06 against a June 30 close of $128.50 (-1.12%).

Lens 3 — insiders: two purchases in the entire parsed record — neither by an officer — against 39 sales. The parsed Form 4 record holds 145 filings through October 2, 2026, and across the full record it contains exactly 2 purchase transactions: 17,832.86 shares for $1,577,499.98, by 2 buyers — and the officer-purchase count is zero in every window. Neither purchase falls in the last year: the 90-day window and the one-year window each hold no purchase transaction at all. Sales run the other way, and every one of them is an officer sale. The last 90 days hold 17 sales: 228,238 shares for $29,977,578.78, by 5 sellers, across 10 filings. The one-year window holds 35 sales for $72,013,811.15 (11 sellers), and the full record holds 39 sales for $73,802,886.46 (11 sellers). Every window's implied price sits inside its price range on our file — 90-day sales imply $131.34, one-year sales $123.24, full-record sales $121.89 and the two purchases $88.46 — so share counts and dollar totals are cited for every window. The site's insider aggregate agrees with the full parse on the 90-day window exactly (methodology).

Lens 4 — Congress: one House member, one purchase, no sale. The combined record (as of October 3, 2026) and the House aggregate (as of October 3, 2026) each carry the same single row: one member, recorded with 1 purchase and 0 sales, the latest purchase dated August 19, 2026. The Senate aggregate (as of October 1, 2026) carries no row. The aggregates record counts and dates, not amounts, so that is the whole of this lens.

Lens 5 — the 5% register: 3 filings, every one of them passive, maximum 10.02%. Our full parse holds 3 SC 13D/G filings matching the site aggregate — 0 SC 13D family and 3 SC 13G family (1 SC 13G, 2 SC 13G/A); 2 amendments, 2 reporter names across 3 reporter rows. The maximum is 10.02%: The Vanguard Group printed 253,257,639 shares at 10.02% as of February 28, 2025 (filed March 6, 2025, SC 13G/A). The register's latest filing is Vanguard Capital Management at 186,323,766 shares and 7.53% as of March 31, 2026 (filed April 30, 2026, SC 13G). The remaining print is The Vanguard Group at 0 shares and 0.0% as of March 13, 2026 (filed March 27, 2026, SC 13G/A), recorded as filed. The 439,581,405-share total counts reporter rows across dates, not distinct stakes.

Lens 6 — short interest: two settlements of rebuilding, to 1.40% of the share count. The latest FINRA settlement, September 15, 2026, records 34,430,712 shares sold short — 1.40% of the 2,467,171,638 shares outstanding — at 4.23 days to cover, up 13.68% from the prior settlement (30,287,347 on August 31, 2026). The series peak across all 137 settlements is 41,933,919 shares on April 15, 2025, so the latest reading sits 17.9% below it; against June 30, 2026 (31,381,267) the latest is up 9.7%, and against a year ago (27,709,865 on September 15, 2025) up 24.3%. The recent path falls three times then rises twice: 31,381,267 (June 30), 29,359,028 (July 15), 28,281,375 (July 31), 24,506,520 (August 14), 30,287,347 (August 31) and 34,430,712 (September 15). The series contains no single-settlement step at or above 2 times (methodology).

The Gap

The narrative arriving this week is a trending-screen story: one of the most-watched names on Zacks.com this month, on a stock up 61.2% in a year. The June tape backs the breadth and not the urgency. The full market did add — 87 more filers and 17.29% more shares in a quarter when the price rose 6.8% — but the tracked cohort's verified register barely moved: +0.4% between the same 19 holders, with the largest holder, at 53.6% of the stake, cutting 2.4%, and the two post-June tracked moves on file both decreases (-3.4% and -3.0% in the third quarter). Inside the company, the record holds two purchases ever — neither by an officer, neither in the last year — against 39 sales, every one an officer sale, $29,977,578.78 of them in the last 90 days. The 5% register holds three passive prints, its maximum a 10.02% Vanguard Group print as of February 2025. And the borrow has turned: after three falls it has risen in two straight settlements, to 24.3% above its year-ago level. One plausible reading is that the year's run was carried by broad-market accumulation while the tracked register, the insiders and — lately — the shorts all leaned the other way; the trending slot measures attention, and none of the six lenses shows the tracked money chasing it.

What Would Change the Picture

Nothing above is a recommendation. These filings would change it:

• 1. The 2026Q3 13F season (filing window closing mid-November 2026). Two holders have already filed at September 30 — Sarasin & Partners (711,274 shares, down 3.4% on the quarter) and David Katz - Matrix Asset Advisors (1,621 shares, down 3.0%) — and both cut. Whether Bill Nygren - Oakmark Funds' 12,073,109-share position — 53.6% of the June stake, after a 2.4% cut — is held, rebuilt or cut further, and whether the June cohort's verified +0.4% turns into a direction, decides whether this lens stays flat.
• 2. A first officer purchase, or any purchase inside a year. The record holds 2 purchases in 145 filings — neither an officer purchase, neither in the last year — against 39 officer sales. A first recorded officer purchase, at any size, would change this lens.
• 3. A second Congress row, or a Senate row. One House member accounts for the entire Congress lens, with one purchase and no sale. A transaction from any other member — or a first Senate row — would change this lens.
• 4. A first SC 13D filing, or a new 5% print above 10.02%. All three filings in this register are 13G-family filings. A first activist-form filing, or any print above The Vanguard Group's 10.02% maximum, would change this lens.
• 5. Short interest through the April 2025 peak, or back below the August trough. The borrow stands at 34,430,712 shares, 17.9% below the series peak of 41,933,919 and up 24.3% year over year, at 1.40% of the share count. A reading above 41,933,919 would set a new series record; a fall back below 24,506,520 (August 14, 2026) would unwind the two-settlement rebuild.

Related reading: Seven of 147: Every KLA Holder Is Labelled an Increase — Split-Adjusted, the Cohort Grew 1.3% in a Quarter When the Price Rose 104.9% — Filing Tape #130; Eight of 147: Chris Hohn - TCI's New Position Is 36.9% of the Tracked Vulcan Materials Stake, and the Verified Cohort Grew 5.7% in a Quarter When the Price Rose 8.3% — Filing Tape #129. Merck's own page: Merck (MRK) on GetCoattail.

Methodology and data notes

• As-of & limits: The lenses rest on different clocks, none live: 13F is a June 30, 2026 snapshot published up to 45 days later (with two holders' early September 30, 2026 filings, flagged wherever they appear); Form 4 runs through October 2, 2026; Congress aggregates run through October 3, 2026 (Senate through October 1, 2026); 13D/G through April 30, 2026; short interest through September 15, 2026; the price file ends October 2, 2026. Six limits are specific to this audit. First, the roster expanded before the recent audits — from 85 managers (83 filing) to 149 (147 filing) — so "of 147" counts are not comparable to earlier pieces' "of 83" figures. Second, this name carries a period split: 19 tracked holders sit on a June 30, 2026 period-end and two early filers on September 30, 2026; the two groups are reported separately throughout, and the 21-holder collection total is never used as a single-date figure. Third, one early filer's second-quarter register row sits under a filing-agent accession prefix that June-cohort filings also use, so the prefix-based leftover method cannot attribute it; it is attributed instead by full-register residual (below), and its label reproduces exactly from that row. Fourth, the full-market aggregate sums two CUSIPs: share and value totals cross-check exactly against the by-CUSIP fixtures, while filer-count sums exceed the by-ticker counts by exactly one on the current, long and prior filer counts — one filer reports both CUSIPs and is counted once in the by-ticker file; the difference is de-duplication, not disagreement, and the legacy CUSIP is 374,118 shares, 0.02% of the total. Fifth, the two insider purchases in the record are not officer purchases — the officer-purchase count is zero in the 90-day, one-year and full-record windows — and neither purchase falls inside the last year, so this audit does not describe insiders as recent buyers. Sixth, our price file begins June 1, 2021, so every price statement in this audit is mechanical, a date and a close from that file; the file's only split entry is a 1.048 factor dated June 3, 2021 (a spin-off adjustment), which does not touch any comparison in this audit. The Zacks trending-stock note (October 15, 2026) postdates the 13F snapshot and the short-interest series; it is known to this audit only from outside coverage, not from our own files, and none of its figures are cited here beyond the most-watched listing itself, reported as screen content in The Hype; every price figure here is from our own price file.
• Superinvestor lens: 147 managers in the collection (of a 149-manager roster; 144 at a June 30, 2026 period-end and 3 early filers at September 30, 2026, two of them holding this name) collected directly from SEC EDGAR Form 13F (managers_13f collection, regenerated October 15, 2026 for the expanded roster); Merck positions are counted on the single common CUSIP 58933Y105, long rows only, and there are no option rows for this name in the collection. Twenty-one distinct managers hold long positions: 19 at June 30, 2026, totalling 22,519,230 shares worth $2,897,256,403, and two at September 30, 2026 — Sarasin & Partners (711,274 shares, $103,355,227) and David Katz - Matrix Asset Advisors (1,621 shares, $235,548) — for a 21-holder collection total of 23,232,125 shares worth $3,000,847,178 that mixes period-ends and is not quoted as a single-date figure. The June direction count is 8 INCREASED, 5 UNCHANGED and 6 DECREASED; both early filers are labelled DECREASED (Sarasin -3.4%, Matrix -3.0%), and those labels are second-to-third-quarter changes, not merged into the June count. Bill Nygren - Oakmark Funds' share of the June stake is 53.6% = 12,073,109 / 22,519,230; Thornburg Investment Management's is 16.8% = 3,787,976 / 22,519,230; the top two together are 70.4% of the June stake; the early filers' share of the mixed collection total is 3.1% = 712,895 / 23,232,125. All 19 June continuing holders verify row by row against the first quarter under two methods that agree exactly — the generic filing-agent-prefix pairing and the corrected accession-identity / CUSIP-overlap pairing — so the verified continuing total is 22,422,956 shares at March 31 moving to 22,519,230 at June 30 (+0.4%), with no unverified June holder, no new holder and no exit. Sarasin's label is checked against the pipeline second-quarter register, where the one register row for this CUSIP not claimed by a June cohort accession under its own prefix family is Sarasin's 736,662 shares — and 711,274 / 736,662 − 1 = -3.4% reproduces the label exactly; Sarasin's register path runs 785,691 shares in the first quarter to 736,662 in the second (-6.2%) before its September holding of 711,274. Matrix's second-quarter row cannot be isolated that way — it sits under accession 0001172661-26-002637, whose prefix June-cohort filings also use — so it is attributed by residual: the second-quarter register total (23,257,563) minus the verified June cohort (22,519,230) minus Sarasin's row (736,662) leaves 1,671 shares, which is exactly that accession's Merck row, and 1,621 / 1,671 − 1 = -3.0% reproduces Matrix's label exactly; the same residual in the first quarter is also 1,671 shares (accession 0001172661-26-001524), so Matrix's register path is flat into the second quarter before its September holding of 1,621. The pipeline register totals reconcile in both quarters once the period split is included (21 rows and 23,210,318 shares in the first quarter, equalling the verified continuing total plus the two early filers' first-quarter rows, 22,422,956 + 785,691 + 1,671; 21 rows and 23,257,563 shares in the second, equalling the June cohort plus the two early filers' second-quarter rows, 22,519,230 + 736,662 + 1,671 — a register change of +0.2%). Implied per-share value: 17 of the 19 June rows imply exactly $128.50, the June 30, 2026 close (the exceptions are Prem Watsa - Fairfax Financial Holdings at $128.39, Thomas Russo - Gardner Russo & Quinn at $128.51 and DJE Kapital at $130.98), so the June subtotal implied price is $128.66, +0.12% against the close; both September rows imply exactly $145.31, the September 30, 2026 close, 0.0% against their own period's close. The blended collection total implies a mix of two period-ends that this audit does not quote as a price.
• Full-market lens: SEC Form 13F Data Sets full-market aggregation. The primary table is the full13f collection's by-ticker file (holders = distinct filers reporting any of the ticker's CUSIPs; 3,779 reported long positions out of 3,793 filers). Merck carries two CUSIPs in this aggregation (58933Y105 and the legacy 589331107), and the backfill fixtures' by-CUSIP rows sum to the by-ticker row exactly on shares (1,958,408,042 + 374,118 = 1,958,782,160), reported value ($248,844,377,357 + $48,074,154 = $248,892,451,511) and prior reported value; on filer counts the sums exceed the by-ticker counts by exactly one (3,794 vs 3,793 current holders; 3,780 vs 3,779 long; 3,707 vs 3,706 prior), because one filer reports both CUSIPs and the by-ticker file counts distinct filers. The by-ticker file's entered/exited fields (2,118 and 2,031, a net of +87 that matches the change in holder count) are gross flows, so this audit headlines the net change. Reported-value caution: the aggregate value ($248,892,451,511 over 1,958,782,160 shares) implies $127.06 per share against a June 30, 2026 close of $128.50 in our price file, a gap of -1.12% — printed here as found. The aggregate sums the VALUE of every information-table row — including put and call option rows — while the share count covers long common-stock rows only, so we headline filer and share counts and label dollar values "reported."
• Insider lens: Form 4 full parse (agg_by_ticker, as of October 2, 2026) is the basis here; the site's insider aggregate (90-day window) agrees with it exactly for this name — 0 purchases, 17 sales, $29,977,578.78, 5 sellers — so no disagreement needs stating. Implied prices: 90-day sales $131.34 (window closes $120.78–$156.45), one-year sales $123.24 (window closes $82.49–$156.45), full-record sales $121.89 and full-record purchases $88.46 (full-file closes $71.68–$156.45) — every implied price inside its window's range.
• Market context sources: the Zacks trending-stock note "Here is What to Know Beyond Why Merck & Co., Inc. (MRK) is a Trending Stock" (October 15, 2026), which describes Merck as one of the stocks most watched by Zacks.com visitors lately. Figures we could not confirm were left out; the external items above are reported speech from that outlet, not GetCoattail measurements.
• Merck is in the GetCoattail stock-page universe: Merck (MRK) stock page. Series data: mrk_lens_data.csv · mrk_short_interest_series.csv. Earlier audits: KLA · Vulcan Materials.

Past patterns are not a promise of future results. For education only — not investment advice.

This article describes public filings as of the dates stated. It is not investment advice and makes no recommendation. Filings lag reality: 13F positions are as of June 30, 2026, and later trading is not yet public.

Revision history: v1.0 — October 20, 2026: first publication. v1.1 — October 20, 2026: corrected The Hype's sourcing — v1.0 described Merck as fourth on TipRanks' trending list, based on a non-default screener view; the trending reference is now Zacks' October 15, 2026 most-watched note. No filing figure changed, and no conclusion is affected. v1.2 — October 20, 2026: narrowed the v1.1 note to what re-checking could verify — the default TipRanks list does not show Merck in its readable top rows, and the non-default view behind v1.0's ranking could not be reproduced, so its exact settings are not asserted here.