# What Is a CUSIP Number? Structure, Uses, and Lookup Published: 2026-04-19 Author: Warren Team URL: https://www.heywarren.com/blog/cusip-number --- When you buy 100 shares of Apple in your Schwab account, the actual security gets identified by its CUSIP number, 037833100, not the ticker symbol "AAPL." That nine-character code is what travels through clearing houses, settles trades at the DTCC, and shows up on the 1099 your broker mails out in February. CUSIPs are the financial industry's social security numbers for securities, and almost every back-office system in North America depends on them. Most retail investors never see a CUSIP number. You search for "Apple," click buy, and your broker handles the rest. But the moment something goes wrong, a lost stock certificate, a tax form mismatch, an inherited bond with no obvious [issuer](/blog/issuer), the CUSIP becomes the only piece of information that matters. Knowing how to read one, where to find one, and how it differs from a ticker or an ISIN turns confusing paperwork into solvable problems. I've spent years on the operations side of markets, and I'll explain what a CUSIP number actually is, how the nine characters break down, why the system exists, and where you'll encounter CUSIPs in your own portfolio. By the end you'll be able to decode one at a glance and know exactly which security it points to. ## What Is a CUSIP Number? A CUSIP number is a nine-character alphanumeric code that uniquely identifies a security issued in the United States or Canada. The acronym stands for Committee on Uniform Securities Identification Procedures, and the codes are assigned by CUSIP Global Services, a business owned by S&P Global. Every stock, bond, and fund traded in North America has one. The CUSIP system was created in 1968 by the American Bankers Association to standardize back-office processing. Before CUSIPs, brokers used handwritten ticker symbols and inconsistent abbreviations on every trade ticket, which made reconciling trades between firms a nightmare. The standardized nine-character format gave clearing firms a single, unambiguous identifier for any security. Today, CUSIPs are embedded in essentially every piece of securities infrastructure: trade confirmations, custody records, regulatory filings, tax documents, and corporate-action notices. The [Depository](/blog/what-is-a-depository) Trust & Clearing Corporation (DTCC) uses CUSIPs as the primary key for the trillions of dollars in securities it holds in book-entry form. ## CUSIP Number Structure A CUSIP breaks into three parts that each carry specific information about the security. The first six characters identify the issuer, the next two identify the specific issue, and the final character is a mathematically derived check digit that catches transposition errors. Reading these three components tells you who issued the security and what flavor it is. ![A CUSIP breaks into three parts: a six-character issuer code, a two-character issue code, and a single check digit.](data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20600%20211%22%20width%3D%22600%22%20height%3D%22211%22%20role%3D%22img%22%3E%3Ctitle%3EHierarchy%3C%2Ftitle%3E%3Crect%20width%3D%22100%25%22%20height%3D%22100%25%22%20fill%3D%22%23f8fafc%22%2F%3E%3Crect%20x%3D%22220%22%20y%3D%2220%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22%232563eb%22%2F%3E%3Ctext%20x%3D%22300%22%20y%3D%2254%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22700%22%20fill%3D%22white%22%3ECUSIP%20%289%20chars%29%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20120%20105.5%20L%20120%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%2240%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22120%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3EChars%201%E2%80%936%3C%2Ftext%3E%3Ctext%20x%3D%22120%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3EIssuer%20code%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20300%20105.5%20L%20300%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%22220%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22300%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3EChars%207%E2%80%938%3C%2Ftext%3E%3Ctext%20x%3D%22300%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3EIssue%20code%3C%2Ftext%3E%3Cpath%20d%3D%22M%20300%2078%20L%20300%20105.5%20L%20480%20105.5%20L%20480%20133%22%20stroke%3D%22%23cbd5e1%22%20stroke-width%3D%222%22%20fill%3D%22none%22%2F%3E%3Crect%20x%3D%22400%22%20y%3D%22133%22%20width%3D%22160%22%20height%3D%2258%22%20rx%3D%228%22%20fill%3D%22white%22%20stroke%3D%22%230891b2%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22480%22%20y%3D%22158%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2213%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3EChar%209%3C%2Ftext%3E%3Ctext%20x%3D%22480%22%20y%3D%22176%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2210%22%20fill%3D%22%2364748b%22%3ECheck%20digit%3C%2Ftext%3E%3C%2Fsvg%3E) *A CUSIP breaks into three parts: a six-character issuer code, a two-character issue code, and a single check digit.* ### Characters 1-6: The Issuer Code The first six characters identify the company, government, or fund that issued the security. Every issuer gets a single base code that follows it across all of its outstanding securities. Apple Inc. for example, owns the issuer code "037833," and every Apple security, common stock, debt, preferred, starts with those six characters. Issuer codes are assigned roughly in the order companies registered with CUSIP Global Services, which is why older companies often have lower numbers. The codes mix digits and letters once the numeric space fills up. ### Characters 7-8: The Issue Code The seventh and eighth characters identify the specific security within an issuer's family. Common stock typically gets "10," with subsequent issues incrementing from there. Bonds, preferred shares, warrants, and different share classes each receive their own issue suffix, which is why a single company can have dozens of CUSIPs. For bonds, the issue code distinguishes between maturities and coupon rates. A company with twelve outstanding bond issues has twelve different CUSIPs, even though all twelve start with the same issuer code. ### Character 9: The CUSIP Check Digit The ninth character is a check digit calculated from the first eight using a modulus-10 algorithm. If someone fat-fingers a CUSIP into a trade ticket and transposes two characters, the check digit will fail validation and the system rejects the entry before settlement. It's a low-tech but extremely effective error catcher that has prevented countless mis-bookings. ### A Worked Example: Apple Inc. Apple's common stock CUSIP is 037833100. Broken down: "037833" identifies Apple as the issuer, "10" identifies the security as common stock, and "0" is the check digit confirming the other eight characters are internally consistent. Tesla, Microsoft, and Berkshire Hathaway each have their own issuer codes following the same pattern. ## CUSIP vs Ticker Symbol A ticker symbol is built for trading; a CUSIP is built for identification and settlement. Tickers like AAPL or TSLA are short, memorable, and exchange-specific, useful for placing an order on a screen. CUSIPs are longer, never reused, and survive ticker changes, exchange transfers, and corporate actions that would otherwise create ambiguity. Tickers can be recycled. When a company delists or goes bankrupt, its ticker often gets reassigned to a new firm within a few years. CUSIPs are permanent and tied to the specific security, so historical records remain intact even when the ticker space gets reused. This is why every regulatory filing, tax form, and clearing record references the CUSIP rather than the ticker. Bonds and many mutual funds don't have tickers at all, but they always have CUSIPs. If you own a corporate bond, the only standard identifier on your statement will be the nine-character CUSIP plus a description of the coupon and maturity. ## CUSIP vs ISIN, SEDOL, and WKN Outside North America, securities use different identifier systems. The International Securities Identification Number (ISIN) is the global standard, twelve characters consisting of a two-letter country code, the nine-character national identifier, and a final check digit. For US securities, the national identifier embedded in the ISIN is literally the CUSIP. ![A US ISIN wraps the nine-character CUSIP between a two-letter country code and a recomputed check digit.](data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%20875%20125%22%20width%3D%22875%22%20height%3D%22125%22%20role%3D%22img%22%3E%3Ctitle%3EFlow%20diagram%3C%2Ftitle%3E%3Crect%20width%3D%22100%25%22%20height%3D%22100%25%22%20fill%3D%22%23f8fafc%22%2F%3E%3Crect%20x%3D%2230%22%20y%3D%2225%22%20width%3D%22170%22%20height%3D%2275%22%20rx%3D%2210%22%20fill%3D%22white%22%20stroke%3D%22%232563eb%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22115%22%20y%3D%2258.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ECountry%20code%3C%2Ftext%3E%3Ctext%20x%3D%22115%22%20y%3D%2278.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2211%22%20fill%3D%22%2364748b%22%3E%26quot%3BUS%26quot%3B%20%282%20chars%29%3C%2Ftext%3E%3Cline%20x1%3D%22205%22%20y1%3D%2262.5%22%20x2%3D%22237%22%20y2%3D%2262.5%22%20stroke%3D%22%2364748b%22%20stroke-width%3D%222%22%2F%3E%3Cpolygon%20points%3D%22244%2C62.5%20235%2C57.5%20235%2C67.5%22%20fill%3D%22%2364748b%22%2F%3E%3Crect%20x%3D%22245%22%20y%3D%2225%22%20width%3D%22170%22%20height%3D%2275%22%20rx%3D%2210%22%20fill%3D%22white%22%20stroke%3D%22%232563eb%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22330%22%20y%3D%2258.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3ECUSIP%3C%2Ftext%3E%3Ctext%20x%3D%22330%22%20y%3D%2278.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2211%22%20fill%3D%22%2364748b%22%3E9%20chars%3C%2Ftext%3E%3Cline%20x1%3D%22420%22%20y1%3D%2262.5%22%20x2%3D%22452%22%20y2%3D%2262.5%22%20stroke%3D%22%2364748b%22%20stroke-width%3D%222%22%2F%3E%3Cpolygon%20points%3D%22459%2C62.5%20450%2C57.5%20450%2C67.5%22%20fill%3D%22%2364748b%22%2F%3E%3Crect%20x%3D%22460%22%20y%3D%2225%22%20width%3D%22170%22%20height%3D%2275%22%20rx%3D%2210%22%20fill%3D%22white%22%20stroke%3D%22%232563eb%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22545%22%20y%3D%2258.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3EISIN%20check%3C%2Ftext%3E%3Ctext%20x%3D%22545%22%20y%3D%2278.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2211%22%20fill%3D%22%2364748b%22%3E1%20char%3C%2Ftext%3E%3Cline%20x1%3D%22635%22%20y1%3D%2262.5%22%20x2%3D%22667%22%20y2%3D%2262.5%22%20stroke%3D%22%2364748b%22%20stroke-width%3D%222%22%2F%3E%3Cpolygon%20points%3D%22674%2C62.5%20665%2C57.5%20665%2C67.5%22%20fill%3D%22%2364748b%22%2F%3E%3Crect%20x%3D%22675%22%20y%3D%2225%22%20width%3D%22170%22%20height%3D%2275%22%20rx%3D%2210%22%20fill%3D%22white%22%20stroke%3D%22%232563eb%22%20stroke-width%3D%222%22%2F%3E%3Ctext%20x%3D%22760%22%20y%3D%2258.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2214%22%20font-weight%3D%22600%22%20fill%3D%22%230f172a%22%3EISIN%3C%2Ftext%3E%3Ctext%20x%3D%22760%22%20y%3D%2278.5%22%20text-anchor%3D%22middle%22%20font-family%3D%22system-ui%2C-apple-system%2Csans-serif%22%20font-size%3D%2211%22%20fill%3D%22%2364748b%22%3E12%20chars%20total%3C%2Ftext%3E%3C%2Fsvg%3E) *A US ISIN wraps the nine-character CUSIP between a two-letter country code and a recomputed check digit.* Apple's ISIN, for example, is US0378331005: "US" for the country, "037833100" for the CUSIP, and "5" as the ISIN check digit. This makes converting between CUSIP and ISIN trivial for North American securities, you essentially wrap the CUSIP in a country code and recompute the final digit. Other regions have their own national identifiers. The UK uses SEDOL (Stock Exchange Daily Official List), a seven-character code maintained by the London Stock Exchange. Germany uses WKN (Wertpapierkennnummer), a six-character code historically assigned by Deutsche Börse. ISINs roll all of these up into a single global format, but locally each market still uses its native identifier for day-to-day operations. ## Securities That Get CUSIPs Almost every tradable security issued in the US or Canada gets a CUSIP. The system covers stocks, bonds, funds, and structured products with equal coverage, though the issuance process and fee structure differ slightly across asset classes. - **Common and preferred stocks**, Each share class gets its own CUSIP, which is why Berkshire Hathaway's Class A and Class B shares have distinct codes. - **Corporate bonds**, Every bond issue gets a unique CUSIP, distinguishing maturities, coupons, and seniority. - **Municipal bonds**, Each maturity within a single bond deal typically receives its own CUSIP, so a single muni offering can generate dozens of identifiers. - **US Treasury securities**, Bills, notes, bonds, and TIPS all carry CUSIPs assigned by the Treasury through CUSIP Global Services. - **Mutual funds**, Each share class (A, C, I, R, etc.) of every fund gets a separate CUSIP. - **ETFs**, Including index funds and actively managed ETFs, each ticker corresponds to a single CUSIP. - **Structured products**, Notes, certificates, and other custom-issued instruments carry CUSIPs to enable clearing. - **American Depositary Receipts**, ADRs representing foreign companies trading in the US get their own ADR CUSIP separate from the underlying foreign share. ## Where CUSIP Numbers Are Used CUSIPs are the connective tissue of securities operations. Every system that needs to know what security is involved in a [transaction](/blog/what-is-a-transactions) uses the CUSIP as the primary identifier, not the ticker or the company name. Most of these uses are invisible to retail investors, but they touch your portfolio constantly. ### Clearing, Settlement, and Custody The DTCC clears and settles essentially all US [equity](/blog/equity-meaning-in-business) trades using CUSIP as the security key. When your broker sells your shares, the trade flows through DTCC by CUSIP, with shares moving in book-entry form between custodian accounts. Your broker's internal accounting system also tracks your holdings by CUSIP, even though it shows you tickers on the screen. ### Tax Reporting and 1099 Forms Every 1099-B, 1099-DIV, and 1099-INT your broker issues includes the CUSIP for each reported security. The [IRS](https://www.irs.gov/) uses CUSIPs to match cost basis between brokers when you transfer accounts and to reconcile reported income against issuer disclosures. If a 1099 entry looks wrong, the CUSIP is the fastest way to confirm exactly which security the broker is reporting. ### Lost Securities and Stolen Certificate Searches If you find an old stock certificate in a relative's safe deposit box, the CUSIP printed on it is the key to figuring out what it's worth. The SEC operates a Lost Securities Locator Service, and you can report stolen securities to the FBI through the Securities Lost and Stolen (SLI) database, both systems use the CUSIP as the primary search field. ### Other Uses CUSIPs also appear on trade confirmations, brokerage statements, SEC filings (alongside CIK numbers), bond prospectuses, and corporate-action notices. Anywhere a security needs to be referenced unambiguously, the CUSIP is the identifier of choice. ## How CUSIPs Are Assigned CUSIP Global Services assigns thousands of new CUSIPs every business day. Issuers, or their underwriters and counsel, apply for a CUSIP before a security is offered to the public, paying a fee that scales with the asset class and the number of identifiers requested. Municipal bond deals can generate hundreds of CUSIPs at once because each maturity needs its own. The fee structure has been controversial. Because CUSIP Global Services is the sole licensed source of CUSIPs in North America, S&P Global controls pricing for both new assignments and downstream data licensing. Several lawsuits and regulatory complaints have challenged how broadly CUSIP licensing fees can be enforced on data redistributors and software providers, though the underlying issuer code system remains intact. ## CUSIP vs CIK Number A CUSIP identifies a security; a CIK identifies a filer. The Central Index Key (CIK) is the SEC's permanent identifier for any entity that submits filings to [EDGAR](https://www.sec.gov/edgar), companies, mutual funds, individuals filing 13D disclosures, and so on. One issuer has one CIK but typically multiple CUSIPs, one for each outstanding security. When you pull up a 10-K on EDGAR, you're searching by CIK. When you reconcile a trade or look up a bond, you're using the CUSIP. The two systems coexist because they answer different questions: who filed this, versus what security is this. ## How to Look Up a CUSIP For securities you own, the CUSIP is on every brokerage statement and trade confirmation, usually next to the security description. Bond statements always show the CUSIP prominently because there's often no other unique identifier. Tax documents repeat it for each reported position. For securities you don't own, free lookup options are more limited because CUSIP licensing restricts how broadly the database can be republished. SEC EDGAR shows CUSIPs on many filings, especially prospectuses and 13F holdings reports. Bloomberg Terminals, FactSet, and Refinitiv all expose CUSIP search to subscribers. Several broker websites let you search a CUSIP within their research tools, even for securities you don't hold. ## Common Confusions A few CUSIP edge cases trip up even experienced investors. Stock splits sometimes generate a new CUSIP and sometimes don't, depending on whether the underlying security is reclassified. Spin-offs always create new CUSIPs because the spun-off entity is a brand-new issuer with its own issuer code. Foreign stocks trading directly on overseas exchanges don't have CUSIPs, they have SEDOLs, WKNs, or other national identifiers, all wrapped in ISINs for global use. But ADRs trading on US exchanges do have CUSIPs, assigned to the depositary receipt rather than the underlying foreign share. This is why your broker statement shows a CUSIP for, say, Toyota's ADR but not for Toyota's Tokyo-listed common shares. A single company can easily have dozens of CUSIPs. Multiple share classes, every outstanding bond issue, preferred series, warrants, and tracking stocks each generate a separate identifier. When researching a company's full capital structure, expect to see a long list rather than a single code. ## Authoritative Sources For deeper background and primary-source data on this topic, the following authoritative sources are useful starting points: - [SEC](https://www.sec.gov/) - [Federal Reserve](https://www.federalreserve.gov/) ## Conclusion A CUSIP number is a nine-character identifier that uniquely tags every security issued in the US and Canada. Knowing how to read one, six characters for the issuer, two for the issue, one check digit, turns opaque brokerage paperwork into something you can decode at a glance. Five takeaways worth remembering: 1. **CUSIPs identify securities; tickers identify trading symbols.** Use the CUSIP whenever permanence and precision matter, tax forms, transfers, lost certificates, and bond research. 2. **The first six characters belong to the issuer.** Every Apple security starts with "037833," and that consistency makes capital-structure research much faster. 3. **ISINs wrap CUSIPs for global use.** A US ISIN is just "US" + the CUSIP + a recomputed check digit. 4. **Bonds and mutual funds rely on CUSIPs more than [equities](/blog/what-is-equities) do.** Many fixed-income securities have no ticker at all, so the CUSIP is the only standard identifier. 5. **CUSIP Global Services controls assignment.** Fees and licensing have generated litigation, but the underlying system remains the bedrock of North American securities operations. As tokenization, fractional shares, and 24-hour trading reshape market structure over the next decade, the CUSIP system will likely extend rather than disappear, every new instrument still needs an unambiguous identifier, and the existing infrastructure already speaks CUSIP fluently. Ready to put this knowledge to work? Try Warren, your AI financial advisor, get personalized, conflict-free guidance at heywarren.com --- ## Related Reading **More from Warren**: **Authoritative sources**: - [SEC Investor.gov, Investing Basics](https://www.investor.gov/introduction-investing/investing-basics) - [FINRA, Investor Education](https://www.finra.org/investors)