GetCoattail Research — Costco is the warehouse retailer that just closed a fiscal year with revenue above $300 billion, and it sits third on MarketBeat's October 11 retail watchlist. The filings describe a register that barely touches the stock: seven tracked superinvestors hold it, one of them is 77.7% of the cohort's shares, no tracked manager opened or added to a position in the second quarter, the full market added more than 54 million reported shares in the same quarter, and insiders have recorded no purchase at all in the entire parsed record against 27 sales.
Start with the narrative. Costco reported its fiscal fourth quarter on September 24: net sales of $93.9 billion, up 11.2% from a year earlier, total revenue of $95.723 billion, and diluted earnings of $6.75 a share, a figure the company said included a $0.15-a-share benefit from tariff refunds. Comparable sales rose 9.4%, or 6.7% adjusted for gasoline prices and foreign exchange, and digitally enabled comparable sales rose 19.5%. The full fiscal year brought total revenue of $303.154 billion, up 10.14%, earnings of $20.76 a share, 939 warehouses and 84.1 million paid members. September then extended the run: net sales of $30.02 billion for the five weeks ended October 4, up 13.0%. Analysts, in aggregate, remain constructive but have been trimming at the edges: MarketBeat's count on October 6 was 22 Buy ratings, 10 Hold and 1 Sell, with an average target of $1,046.27, after Deutsche Bank cut its target to $1,079 on September 28 and Jefferies cut its target to $1,100 on September 25. Our own price file, which ends October 2, puts the last close at $920.65 — down 15.9% from the 252-session closing high of $1,094.32 set on May 19, 2026, up 8.3% from the 252-session closing low of $850.00 set on December 22, 2025, and up 6.8% year to date on that file.
Now the filings. For Costco — the fiftieth Filing Tape audit — the tape shows a tracked cohort that is small, concentrated and shrinking slightly, a broad register that added heavily in the same quarter, an insider record with no purchases at all, and a 5% register that is, again, a Vanguard hand-off.
Lens 1: the superinvestors — seven holders, 50,403 shares, and one holder at 77.7%
We track 83 large, mostly long-only managers whose 13F portfolios we collect directly from SEC EDGAR. As of June 30, 2026, 7 held Costco long — no option rows — totalling 50,403 shares worth $47,150,234. The direction count, on the collection's own labels, is no new positions, no increases, four decreases and three unchanged, with no exits. The cohort total moved from 51,653 shares at March 31 to 50,403 at June 30, a change of -2.42%, a difference of -1,250 shares.
The largest holder is Thomas Gayner's Markel Group, with 39,150 shares worth $36,623,651, a 0.28% portfolio weight, flagged unchanged — 77.7% of the tracked cohort's Costco shares. Every other position is small. Thomas Russo's Gardner Russo & Quinn holds 3,399 shares worth $3,179,709, a 0.04% weight, flagged decreased by 26.5%. Christopher Bloomstran's Semper Augustus holds 3,354 shares worth $3,137,566, a 0.35% weight, flagged decreased by 0.4%. Mairs & Power Funds holds 2,963 shares worth $2,771,798, flagged unchanged. Torray Funds holds 628 shares worth $587,475, flagged unchanged. David Katz's Matrix Asset Advisors holds 551 shares worth $515,137, flagged decreased by 1.4%. Bill Nygren's Oakmark Funds holds 358 shares worth $334,898, flagged decreased by 1.1%. Per-holder quarter changes matched by filing accession agree with the collection's own percentage labels for all seven holders — there is no label mismatch in this register. The cohort's implied price, $935.46 per share, sits effectively on the June 30 close of $935.47. The price fell from $996.43 at March 31 to $935.47 at June 30, a change of -6.1% — the tracked register's small trim happened in a falling quarter, and no holder in it bought.
Lens 2: institutions — 4,200 filers, and a share count up 20.45%
Zoom out to the whole 13F market and the direction reverses. At June 30, 2026, 4,200 institutions reported positions, up 45 from 4,155 at March 31 (+1.08%), and 4,190 reported long positions. Reported shares rose 20.45%, from 265,032,609 to 319,228,365 shares — 54,195,756 more shares than the prior quarter. Reported aggregate value rose 18.05% to $305,534,838,432; the aggregate includes option rows, so we headline filer and share counts and label dollars "reported" (see methodology). The implied value per share, $957.10, sits 2.3% above the June 30 close of $935.47 — a wider gap than most audits in this series, and one more reason the share count, not the dollar total, is the headline figure here. Set the two 13F lenses side by side and they point in opposite directions in the same quarter: the tracked cohort cut 2.42% and added nobody, while the broad market added 45 filers and more than 54 million reported shares.
Lens 3: the 5% register — two filings, all of them 13G paper, and a Vanguard hand-off
Our full parse holds just two SC 13D/G filings for Costco — one SC 13G and one SC 13G/A amendment, and no SC 13D of any kind in the parsed set, 2 reporting-person rows across 2 names, the most recent filed April 29, 2026. The amendment prints zero: in an SC 13G/A filed March 26, 2026, The Vanguard Group prints 0 shares (0.0%) as of March 13, 2026. The register's most recent filing is also its only original filing: Vanguard Capital Management prints 33,256,639 shares (7.49%) as of March 31, 2026 in an SC 13G filed April 29, 2026 — the register's maximum row. Read as filed — and the rows are reported here exactly as filed, never summed — the register describes one Vanguard entity's row at zero and another Vanguard entity's row at 7.49%, the same hand-off pattern this series has now recorded at several large caps. There is no activist paper in this register and no 13D at all: two 13G-family filings, two names, both of them Vanguard.
Lens 4: insiders — no purchases in the entire parsed record, against 27 sales
The parsed Form 4 record holds 68 filings through October 2, 2026. Across the whole record, open-market purchases total exactly 0 transactions — no buyer appears in any window the parse covers. Against that stand 27 sales totalling 44,088.33 shares and $41,725,557.82, by fifteen sellers, 22 of them recorded as officer sales. The last year holds 14 of those sales, totalling 18,570.33 shares and $17,257,376.44 by ten sellers, and no purchases. The recent window is the same shape: the last 90 days hold two sales and no purchases — 3,000.64 shares for $2,748,374.36, by two sellers, both officer sales. Our site's insider aggregate, compiled as of October 12 over its 90-day window, records the same two sales at the same amount, by the same number of sellers, with no purchases; on this lens the two collections agree completely. We assign no motives to any of it; a tape with 27 sales and no purchases in the parsed record is the fact.
Lens 5: Congress — one buy, one sell, and a July buy
Across the congressional record we maintain (combined record as of October 3, 2026), Costco shows one member recorded, one buy transaction and one sell transaction, with a most-recent buy on July 10, 2026, with the Republican party represented. The House aggregate (as of October 3, 2026) carries the whole register: the same one member, the same one buy and one sell, and the same July 10 most-recent buy. The Senate aggregate (as of October 1, 2026) carries no Costco row at all — we report that absence as the aggregate prints it. The register is as balanced as a two-transaction register can be, and its most recent recorded act is a buy.
Lens 6: short interest — 7,360,574 shares, just below a peak set this May
FINRA's files carry the borrow across 137 settlements, from January 15, 2021. As of September 15, 2026 — the most recent settlement — 7,360,574 Costco shares were sold short, with days-to-cover of 3.67, down 2.87% from the prior settlement. That reading sits just below the series maximum: the peak is 7,878,688 shares on May 29, 2026, a fact we verified by taking the maximum across the whole series, and the latest reading sits 6.6% below it. Unlike the older peaks in several earlier audits, this borrow's high is recent — set five settlements before the latest print. Against the fundamentals file's 443,129,349 shares outstanding, that is 1.66% of the share count. Against September 15, 2025 the latest reading is up 12.5% from 6,542,302 shares. The June 30, 2026 settlement — the date the 13F lenses snapshot — printed 7,284,892 shares, so the borrow has edged up since the quarter-end the ownership lenses describe. The recent settlements run 6,957,664 on July 15, then 7,655,966, 7,364,782, 7,577,940 and 7,360,574. The series minimum is 2,974,309 shares on January 31, 2023; the latest reading sits about two and a half times that low.
The borrow set its high this spring and has held near it since. Set beside the ownership lenses, that leaves a register with no urgency in either direction: the tracked cohort is tiny and trimming, the broad market added heavily, and the short side is close to — but not at — its recent peak.
The gap, stated plainly
The narrative describes a retailer whose fiscal fourth quarter grew net sales 11.2% to $93.9 billion, whose September sales then rose 13.0%, rated 22 Buy against 10 Hold and 1 Sell with an average target of $1,046.27 — above the $920.65 close on our price file through October 2 — even as two firms trimmed their targets in late September and the stock sat 15.9% below its May closing high. The tracked superinvestors held 50,403 shares at June 30 across seven holders, having cut the count 2.42% in a quarter when the price fell 6.1%, with no new position and no increase anywhere in the register, and with Markel Group at 77.7% of the cohort on a position it left unchanged. The full market moved the other way, larger: 319,228,365 reported shares, up 54,195,756, across 4,200 filers — 45 more than the prior quarter. The 5% register printed two filings, all of them 13G-family paper and not one a 13D: one Vanguard entity at zero, another at 7.49%. Insiders, across 68 parsed filings, recorded no purchase at all against 27 sales totalling $41,725,557.82. Congress registers one buy and one sell across one member, its most recent act a buy on July 10. And the borrow, at 7,360,574 shares, stands just below a peak it set in May 2026. One plausible reading is that the registers are describing different Costco stories on different clocks: the broad market used the second quarter to add a fifth more reported shares, the tracked cohort — never more than a toehold in this name — trimmed and added nobody, the analysts are paying for a membership-and-sales engine the September print partly supported, the insider tape offers sales and no confirming purchase in its entire history, and short sellers built their largest borrow this spring and have mostly kept it. The record supports each clause separately; it does not say which register is right, and it cannot — the tracked cohort's whole position is a June 30 snapshot of 50,403 shares.
What would change the picture
Nothing above is a recommendation. It is a record. These are the filings that would change the description:
- 1. The 2026Q3 13Fs (filing window closing mid-November 2026). The tracked cohort held 50,403 shares at June 30 across seven holders, after a -2.42% move with no new or increased position. Whether Markel Group's 39,150 shares — 77.7% of the cohort — survive unchanged is the first thing the next register will answer: a cut or exit by Markel would shrink the cohort's register to a residue, and a first new or increased position anywhere in the cohort would break a pattern of zero buying.
- 2. A first insider purchase. The parsed record holds exactly 0 purchase transactions against 27 sales across 68 filings. Any open-market purchase, by any insider, would be the first of its kind in the parsed record and would materially change a one-sided tape.
- 3. An original SC 13D, or a non-Vanguard 13G. The 5% register holds two filings, both 13G-family, two names, both Vanguard entities. A first 13D in the parsed set — any filer declaring an active stake — would change this lens from passive paper into something else.
- 4. Whether the borrow clears its May peak. Short interest stands at 7,360,574 shares, 6.6% below the May 29, 2026 peak of 7,878,688. A settlement above that peak would mark a new high for the borrow; a return below the July 15, 2026 print of 6,957,664 would mark a genuine unwind from the spring high.
- 5. Whether the full market keeps adding. The broad register added 54,195,756 reported shares in the second quarter while the tracked cohort cut. A second straight quarter of broad additions alongside a flat or shrinking cohort would widen the split this audit describes; a broad reversal would close it.
Until one of those prints, the record describes a stock held by seven of our 83 tracked superinvestors — 50,403 shares, down 2.42% in the quarter its price fell 6.1%, with no new or increased position and one holder at 77.7% — whose full market added 45 filers and 54,195,756 reported shares in the same quarter, whose 5% register is two 13G-family filings across two Vanguard names, whose insiders have recorded no purchase and 27 sales in the entire parsed record, whose congressional register holds one buy and one sell with its last act a buy, and whose borrow sits just below a peak set this May — all of it snapshot at June 30, in a quarter the broad market and the tracked cohort read in opposite directions.
Related reading: Ten of 83: Lone Pine Opened a 2.6 Million-Share Home Depot Position as the Cohort Tripled Its Stake — Filing Tape #49; Seven of 83: Every Superinvestor in AbbVie Trimmed or Stood Still in Q2. Its Insiders Have Never Bought a Share. — Filing Tape #48; Zero of 83: The Superinvestors Aren't in IREN — Filing Tape #1. Costco's own page: Costco Wholesale Corporation (COST) on GetCoattail.
Methodology and data notes
- Superinvestor lens: 83 managers collected directly from SEC EDGAR Form 13F (managers_13f collection), positions as of June 30, 2026; Costco identified by CUSIP 22160K105. Seven distinct managers hold long positions totalling 50,403 shares; all seven reported rows are long (no put or call rows); the direction count on the collection's labels is no new, no increased, four decreased and three unchanged, and the collection's exit list contains no Costco row. Quarter-to-quarter cohort totals (51,653 shares at March 31 across seven filing rows; 50,403 shares at June 30 across seven filing rows; change -2.42%) are from the site pipeline's holdings files on the same CUSIP basis in both quarters, and the pipeline's second-quarter share and value totals match the EDGAR collection's long totals exactly (differences of 0 shares and $0). Per-holder quarter changes are matched by filing accession prefix and agree with the EDGAR collection's own percentage labels for all seven holders. Markel Group's share of the cohort is 77.7% = 39,150 / 50,403.
- 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 the CUSIP; 4,190 reported long positions out of 4,200 filers). Costco reports under the single CUSIP 22160K105, and the backfill fixtures' by-CUSIP row for that CUSIP matches the by-ticker row exactly (4,200 filers; 319,228,365 shares; $305,534,838,432 reported; 4,155 prior filers; $258,808,148,709 prior reported value). The by-ticker file's entered/exited fields (2,071 and 2,026, a net of +45 that matches the change in holder count) are gross flows, so this audit headlines the net change. Reported-value caution: the aggregate value ($305,534,838,432 over 319,228,365 shares) implies ≈$957.10 per share against a June 30, 2026 close of $935.47 in our price file, a gap of +2.3%. 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: full-parse Form 4 aggregation (agg_by_ticker), record as of October 2, 2026 (68 filings). Sale and purchase counts are transaction-code counts (S and P) in non-derivative rows; grants and exercises are not counted as purchases, and one filing can contain many transaction rows. Purchase transactions total exactly 0 across the parsed record — and zero in both the 90-day window and the last year. Sale transactions total 27 across the record (44,088.33 shares, $41,725,557.82, fifteen sellers, 22 of them officer sales); the 90-day window holds two of them (3,000.64 shares, $2,748,374.36, two sellers, both officer sales) and no purchases, and the last year holds fourteen (18,570.33 shares, $17,257,376.44, ten sellers). The site's insider aggregate (compiled as of October 12, 2026, 90-day window) records the same two sales — 2 transactions, $2,748,374.36, two sellers — and no purchases, so the two collections agree on this lens in full. "Purchases" in this audit is scoped to this parsed record, whose 68 filings are the coverage stated here.
- 13D/G lens: full-parse SC 13D/G aggregation and parsed filings (2 filings matching issuer CIK 909832 on CUSIP 22160K105, 2 reporting-person rows across 2 names: one SC 13G and one SC 13G/A amendment, no SC 13D filings), filings through April 29, 2026. The site aggregation's COST row counts the same 2 filings. The Vanguard Group's row (0 shares at 0.0% as of March 13, 2026, filed March 26, 2026) and Vanguard Capital Management's row (33,256,639 shares at 7.49% as of March 31, 2026, filed April 29, 2026) are reported as filed, under the reporting-person names exactly as they appear. No rows are summed, because aggregation totals across these rows would add different dates together. No reason for any change is asserted — the filings themselves are the record.
- Congress lens: Senate PTR archive and House PTR archive as maintained on this site, combined record as of October 3, 2026 — one member recorded, one buy transaction and one sell transaction, with a most-recent buy on July 10, 2026, and the Republican party represented. The House aggregate (as of October 3, 2026) carries one member, one buy and one sell with the same most-recent buy date. The Senate aggregate (as of October 1, 2026) carries no Costco row, and this audit reports that absence exactly as the aggregate prints it. The aggregates record counts and dates, not trade sizes, and this audit reports them on that basis.
- Short interest lens: FINRA Equity Short Interest files (biweekly settlement dates), collected directly from FINRA's public distribution. The published series covers 137 settlements from January 15, 2021 (3,594,437 shares) to September 15, 2026. The latest reading is 7,360,574 shares on September 15, 2026, which sits 6.6% below the series maximum of 7,878,688 shares on May 29, 2026 (verified by a maximum query over the series, not read off the latest row), up 12.5% from the September 15, 2025 reading of 6,542,302 and down 2.87% from the prior settlement. The latest row's prior-settlement field (7,577,940) matches the prior settlement file's reported figure exactly. The series minimum is 2,974,309 shares on January 31, 2023. FINRA publishes each settlement about two weeks after the fact. The share-count ratio (1.66%) uses the fundamentals file's shares-outstanding figure below.
- Fundamentals note: our fundamentals collection carries Costco's revenue of $275,235,000,000 labelled fiscal 2025, its net income of $8,099,000,000 labelled fiscal 2025, and its assets of $77,099,000,000 labelled fiscal 2025. The file is marked ok for this name, with no missing fields: shares outstanding of 443,129,349 (as of September 29, 2026, sourced in the file to a dei EntityCommonStockSharesOutstanding count) and a file-computed market value of $414,627,266,026.74. The file's fiscal-year labels predate the company's fiscal 2026 results reported on September 24, 2026 (see market context), and we keep the two sources' figures separate rather than blending them. The file's price for the name is $935.68 as of October 6, 2026; our daily-close file ends October 2, 2026 at $920.65, and we keep the two files' figures separate rather than blending them.
- Prices: our own daily-close file for Costco through October 2, 2026 ($920.65 close, +6.8% year to date on that file; 252-session closing high $1,094.32 on May 19, 2026; 252-session closing low $850.00 on December 22, 2025; closes of $996.43 at March 31, 2026 and $935.47 at June 30, 2026, a second-quarter change of -6.1%; change from June 30 to October 2 of -1.6% ((920.65 / 935.47) − 1)). The drawdown from the 252-session closing high is -15.9%, the gain from the 252-session closing low is +8.3%, and the series in our price file begins June 1, 2021.
- Market context sources: MarketBeat's Top Retail Stocks to Watch list for October 11, 2026 (Amazon first, Home Depot second, Costco third — MarketBeat screener reporting, rechecked October 12, 2026); the company's fiscal fourth-quarter and full-year results as reported in September–October 2026 coverage of the September 24, 2026 release (net sales of $93.9 billion, up 11.2%; total revenue of $95.723 billion; diluted earnings of $6.75 a share including a $0.15-a-share tariff-refund benefit; comparable sales up 9.4%, or 6.7% adjusted; digitally enabled comparable sales up 19.5%; full-year total revenue of $303.154 billion, up 10.14%; full-year earnings of $20.76 a share; 939 warehouses; 84.1 million paid members — company release as reported by Tickeron and ad-hoc-news coverage, cross-checked against each other); the September sales report (net sales of $30.02 billion for the five weeks ended October 4, 2026, up 13.0% — company release via GlobeNewswire as reported by TradingView News); the consensus detail (22 Buy, 10 Hold, 1 Sell across 33 firms; average target $1,046.27 — MarketBeat data as reported October 6, 2026); the Deutsche Bank target cut ($1,091 to $1,079, September 28, 2026) and the Jefferies target cut ($1,130 to $1,100, September 25, 2026), both as reported in October 2026 coverage. Figures we could not confirm against two sources were left out.
- Costco is in the GetCoattail stock-page universe: Costco Wholesale Corporation (COST) stock page. Series data: cost_lens_data.csv · cost_short_interest_series.csv. Earlier audits: Home Depot · AbbVie · IREN.
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 12, 2026: first publication.