What SEC filings does Costco Wholesale Corporation submit to the SEC?

Costco Wholesale Corporation (COST) submits several types of SEC filings including Form 4 (insider transactions), Form 144 (proposed insider sales), 8-K reports (material events such as earnings releases, acquisitions, leadership changes), and periodic reports — the 10-Q (quarterly) and 10-K (annual). All filings are publicly available through SEC EDGAR.

What does a Form 4 filing tell me about COST?

A Form 4 for COST discloses a transaction by a company insider — typically a director, officer, or 10%+ shareholder. It shows the source-reported date, number of shares, price, and updated ownership. These facts do not establish motive or predict future returns.

How do I interpret an 8-K filing from Costco Wholesale Corporation?

An 8-K signals a material event requiring prompt disclosure. Common triggers include earnings pre-announcements, acquisitions, leadership appointments or departures, credit changes, or regulatory actions. Read the item codes inside the filing to understand exactly what was disclosed before drawing conclusions.

What is the difference between a 10-K and 10-Q for COST?

The 10-K is Costco Wholesale Corporation's annual report with fully audited financial statements, comprehensive MD&A, and complete risk factor disclosures — filed 60–90 days after fiscal year-end. The 10-Q is a lighter quarterly report with unaudited financials filed for the first three quarters. Together they provide a continuous financial picture of the company.

Where can I see all COST SEC filings directly on EDGAR?

You can view all historical Costco Wholesale Corporation filings on the SEC EDGAR company page for COST. Each filing card on this page links directly to the original SEC document.

How often does Costco Wholesale Corporation file with the SEC?

Costco Wholesale Corporation files one 10-K per year and up to three 10-Qs per year. Form 4 insider transactions must be reported within two business days of each trade, so the frequency depends on how often insiders are buying or selling COST shares. 8-K filings occur whenever a material event happens — which can be several times per quarter for an active company.

COST SEC Filing News — Costco Wholesale Corporation

Latest SEC filings for Costco Wholesale Corporation (COST) explained in plain English. Covers insider buying and selling (Form 4), proposed insider sales (Form 144), material company events (8-K), and quarterly & annual reports (10-Q / 10-K). StrongBuyAnalytics provides navigation and brief excerpts or summaries; original filings remain at the SEC/source links and were authored by their filers, not StrongBuyAnalytics. Filing dates shown are source dates. Coverage and detection can be delayed or incomplete because of SEC availability, amendments, parsing, caching, or outages. Latest source filing date shown: 2026-10-16.

Costco Wholesale Corporation, together with its subsidiaries, engages in the operation of membership warehouses in the United States, Puerto Rico, Canada, Mexico, Japan, the United Kingdom, Korea, Australia, Taiwan, China, Spain, France, Sweden, Iceland, and New Zealand. It offers merchandise, including sundries, dry groceries, candies, coolers, freezers, liquor, and tobacco; non-food merchandise comprising consumer electronics, appliances, small electrics, health and beauty aids, hardware, lawn…

Sector: Consumer Defensive Industry: Discount Stores Market Cap: $438.3B CIK: 909832

Total Filings

Bullish Classifications

Bearish Classifications

Insider Transactions

Material Events (8-K)

Periodic Reports

Rule-based classifications for COST currently lean bearish. Of the 20 filing records displayed, 4 carry bearish classifications (such as insider sales or negative 8-K disclosures) versus 0 bullish. This does not necessarily signal fundamental deterioration — insiders sell for many reasons — but it is worth monitoring alongside the company's core financial metrics.

COST Filing Activity Snapshot 2026-06-25 — 2026-10-16

Insider Transactions (Form 4)

0 buys vs 4 sells

Net insider selling in this period — insiders sell for many reasons beyond conviction.

Largest Form 144 Filing

$2.02M

Adamo Claudine (Executive Vice President) · 2026-09-30

2,200 shares · Form 4

Form 144 Notices

Proposed insider sales filed — Form 144 is a notice of intent, not a confirmed transaction. Actual sales are confirmed via Form 4.

Insider Transactions 12 · Forms 3, 4 and 5

A Form 4 is filed within two business days of a company insider — an officer, a director, or a holder of more than ten percent of the stock — changing their position in the shares. All 12 filings in this group are Form 4s for Costco Wholesale Corporation.

The difficulty with reading these filings as a group is that a single form type covers transactions that mean entirely different things. An executive spending their own money to buy stock and an executive having shares withheld to pay tax on a vesting grant both appear as a Form 4. Every filing below is therefore tagged with the nature of the underlying transaction, taken from the transaction code reported on the form itself.

Across the 12 insider filings shown, the breakdown is 7 compensation award, 4 open-market sale and 1 gift. 4 of them involved a discretionary open-market trade; the rest are compensation and administrative mechanics.

What each transaction type means

Compensation award ×7: Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.
Open-market sale ×4: The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.
Gift ×1: Shares were transferred as a gift, typically for estate or charitable planning. No sale into the market took place.

Form 4 Open-market sale Insider Selling 2026-10-14

COST insider Wilcox William Richard (Executive Vice President) sold 1,100 shares (~$1.05M)

Wilcox William Richard, listed as Executive Vice President at COSTCO WHOLESALE CORP /NEW, reported an open-market sale of 1,100 COST shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`S`	Open-market sale	1,100	$958.21	$1.05M

Filing: Form 4 (Insider Transaction) Insider: Wilcox William Richard (Executive Vice President) Shares: 1,100 Est. Value: $1.05M

View on SEC EDGAR → Open Filing Document →

Form 4 Open-market sale Insider Selling 2026-09-30

COST insider Frates Caton (Sr. Executive Vice President) sold 800 shares (~$732.7K)

Frates Caton, listed as Sr. Executive Vice President at COSTCO WHOLESALE CORP /NEW, reported an open-market sale of 800 COST shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`S`	Open-market sale	800	$915.93	$732.7K

Filing: Form 4 (Insider Transaction) Insider: Frates Caton (Sr. Executive Vice President) Shares: 800 Est. Value: $732.7K

View on SEC EDGAR → Open Filing Document →

Form 4 Open-market sale Insider Selling 2026-09-30

COST insider Adamo Claudine (Executive Vice President) sold 2,200 shares (~$2.02M)

Adamo Claudine, listed as Executive Vice President at COSTCO WHOLESALE CORP /NEW, reported an open-market sale of 2,200 COST shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`S`	Open-market sale	2,200	$915.93	$2.02M

Filing: Form 4 (Insider Transaction) Insider: Adamo Claudine (Executive Vice President) Shares: 2,200 Est. Value: $2.02M

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Wilcox William Richard (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,129	—	—
`F`	Tax withholding on vested shares	1,934	$902.38	$1.75M

Filing: Form 4 (Insider Transaction) Insider: Wilcox William Richard (Executive Vice President) Shares: 6,063

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Rubanenko Yoram (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,129	—	—
`F`	Tax withholding on vested shares	1,695	$902.38	$1.53M

Filing: Form 4 (Insider Transaction) Insider: Rubanenko Yoram (Executive Vice President) Shares: 5,824

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Riel Pierre (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,552	—	—
`F`	Tax withholding on vested shares	1,561	$902.38	$1.41M

Filing: Form 4 (Insider Transaction) Insider: Riel Pierre (Executive Vice President) Shares: 6,113

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Klauer James C (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,129	—	—
`F`	Tax withholding on vested shares	936	$902.38	$844.6K

Filing: Form 4 (Insider Transaction) Insider: Klauer James C (Executive Vice President) Shares: 5,065

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Jones Teresa A. (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,129	—	—
`F`	Tax withholding on vested shares	1,458	$902.38	$1.32M

Filing: Form 4 (Insider Transaction) Insider: Jones Teresa A. (Executive Vice President) Shares: 5,587

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Frates Caton (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,552	—	—
`F`	Tax withholding on vested shares	1,654	$902.38	$1.49M

Filing: Form 4 (Insider Transaction) Insider: Frates Caton (Executive Vice President) Shares: 6,206

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-09-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

Adamo Claudine (Executive Vice President) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	4,129	—	—
`F`	Tax withholding on vested shares	916	$902.38	$826.6K

Filing: Form 4 (Insider Transaction) Insider: Adamo Claudine (Executive Vice President) Shares: 5,045

View on SEC EDGAR → Open Filing Document →

Form 4 Gift Tax / Compensation Filing 2026-07-14

COST insider Form 4 filed for equity award, exercise, or tax withholding

RAIKES JEFFREY S (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were transferred as a gift, typically for estate or charitable planning. No sale into the market took place.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`G`	Gift	5,249	—	—

Filing: Form 4 (Insider Transaction) Insider: RAIKES JEFFREY S (Director) Shares: 5,249

View on SEC EDGAR → Open Filing Document →

Form 4 Open-market sale Insider Selling 2026-06-25

COST insider DENMAN KENNETH D (Director) sold 885 shares (~$847.3K)

DENMAN KENNETH D, listed as Director at COSTCO WHOLESALE CORP /NEW, reported an open-market sale of 885 COST shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`S`	Open-market sale	885	$957.45	$847.3K

Filing: Form 4 (Insider Transaction) Insider: DENMAN KENNETH D (Director) Shares: 885 Est. Value: $847.3K

View on SEC EDGAR → Open Filing Document →

Proposed Insider Sales 3 · Form 144

A Form 144 is a notice of intent to sell restricted or control securities. It is not a record that anything was sold. Costco Wholesale Corporation has 3 such notices in this period.

The distinction matters because a Form 144 is frequently reported as though it were a completed insider sale. The filer may sell all of the shares covered, some of them, or none at all, and there is no obligation to update the notice either way. A sale that is actually executed by an officer or director shows up separately on a Form 4, which is the filing to check before treating a proposed sale as a real one.

Form 144 Proposed Insider Sale 2026-10-13

COST Form 144 filed for proposed insider sale by Wilcox William Richard (1,100 shares) ~$1.05M

Wilcox William Richard filed a Form 144 with the SEC indicating intent to sell COST (COSTCO WHOLESALE CORP /NEW) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Wilcox William Richard Shares: 1,100 Est. Value: $1.05M

View on SEC EDGAR → Open Filing Document →

Form 144 Proposed Insider Sale 2026-09-29

COST Form 144 filed for proposed insider sale by Adamo Claudine (2,200 shares) ~$2.02M

Adamo Claudine filed a Form 144 with the SEC indicating intent to sell COST (COSTCO WHOLESALE CORP /NEW) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Adamo Claudine Shares: 2,200 Est. Value: $2.02M

View on SEC EDGAR → Open Filing Document →

Form 144 Proposed Insider Sale 2026-09-29

COST Form 144 filed for proposed insider sale by Frates Caton (801 shares) ~$733.3K

Frates Caton filed a Form 144 with the SEC indicating intent to sell COST (COSTCO WHOLESALE CORP /NEW) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Frates Caton Shares: 801 Est. Value: $733.3K

View on SEC EDGAR → Open Filing Document →

Material Events 4 · Form 8-K

An 8-K reports a material event in the window between scheduled reports. There are 4 in this period for Costco Wholesale Corporation. Each 8-K names the item number it is filed under, and that number is the fastest way to tell a routine disclosure from a consequential one.

Item 2.02 is an earnings release, Item 5.02 is a change of directors or officers, and Item 1.01 or 2.01 covers a material agreement or a completed acquisition. Item 7.01 and Item 8.01 are the general-purpose disclosure items and carry no fixed meaning on their own.

Form 8-K Material Company Update 2026-10-16

COST filed 8-K — material company event

COSTCO WHOLESALE CORP /NEW filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Form 8-K Material Company Update 2026-10-14

COST filed 8-K — material company event

COSTCO WHOLESALE CORP /NEW filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Form 8-K Material Company Update 2026-09-24

COST filed 8-K — material company event

COSTCO WHOLESALE CORP /NEW filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Form 8-K Material Company Update 2026-07-08

COST filed 8-K — material company event

COSTCO WHOLESALE CORP /NEW filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Periodic Reports 1 · Forms 10-K and 10-Q

The periodic reports are where the audited and reviewed financial statements live. This period contains 1 annual report (10-K) for Costco Wholesale Corporation.

The two are not equivalent in weight. A 10-K is audited by an external firm and includes the full risk factor disclosure, business description and management discussion; a 10-Q is unaudited, reviewed rather than examined, and much shorter. When a figure in a quarterly report is later revised, the annual report is usually where the correction appears.

An amended report — 10-K/A or 10-Q/A — restates or corrects something in the original filing, and is worth reading against the version it replaces.

Form 10-K Annual Report 2026-10-07

COST filed Annual Report (10-K)

COSTCO WHOLESALE CORP /NEW filed its annual report with the SEC. This report includes audited financial statements, business overview, risk factors, and management discussion.

Filing: 10-K (Annual Report)

View on SEC EDGAR → Open Filing Document →

How we classify Costco Wholesale Corporation's filings

Straight from EDGAR

Each displayed record links to an original source document. StrongBuyAnalytics provides navigation and brief excerpts or summaries, not the filing itself. Parsing may omit context or contain errors, so read the original document in full.

Transaction codes, not guesswork

The nature shown on each insider filing comes from the transaction code the filer entered on the form itself — P for an open-market purchase, A for a compensation award, F for shares withheld to pay tax, M for an option exercise. Where one filing contains several codes, the transaction table lists them line by line.

Why the distinction matters

Insider activity is routinely summarised as buying or selling, which flattens together decisions that mean very different things. Shares withheld for tax on a vesting grant are an automatic administrative step; shares bought on the open market are someone committing their own money at the current price.

What this page does not tell you

A filing records what happened, not why. Form 4 does not always disclose whether a sale was executed under a pre-arranged Rule 10b5-1 plan, and no single filing is a basis for a decision on COST. Read these alongside the fundamentals rather than in isolation.

Frequently Asked Questions — COST SEC Filings

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COST Full Analysis

Publisher, sources & limitations — September 15, 2026. StrongBuyAnalytics provides navigation and brief excerpts or summaries for educational use. Original filings remain at SEC EDGAR or other displayed source links; StrongBuyAnalytics does not author them. Filing dates are source dates, not publication dates for this page. Coverage can be delayed, incomplete, amended, or unavailable because of SEC/source availability, parsing, caching, or outages. Verify every material statement in the original filing.

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