Take NVDA. It exists as tokens from four issuers, across five chains, at seven separate contract addresses. Each address has its own supply and its own holder count.
So how many things is that? The answer decides what a reader sees.
Three levels, not one
A stock is the company's share. NVDA. There is one of it, and nobody on a blockchain created it.
An instrument is one issuer's product for one stock. It carries one legal wrapper, one eligibility rule, and one way of handling dividends. Robinhood's NVDA token and Ondo's NVDA token are two instruments, because the wrapper, the rule and the dividend mechanic are all different. NVDA has four.
A listing is one instrument on one chain, with one contract address. Ondo puts its NVDA instrument on Ethereum, BNB Chain and Solana: three listings, three addresses, one instrument, because it is the same claim on the same vehicle with the same synthetic share value. Three addresses do not make three products. Backed does the same on a smaller scale, with its NVDA certificate on Solana and Ethereum. Add Robinhood and Dinari, one listing each, and NVDA reaches seven listings.
Across the whole site that comes out as 194 stocks, 431 listings, four issuers and five chains. The two middle levels explain the entire gap between 194 and 431.
Why we bothered
The alternative produces a lie.
Flatten the model and treat every listing as a thing, and NVDA appears seven times on the board. A reader scanning it sees seven NVDAs and reasonably concludes there are seven things to choose between, ranked by whatever order they happen to be in. That is a shopping aisle, and putting a choice in front of someone is a step away from advising them.
Flatten it the other way, treating every issuer's token as interchangeable, and you end up printing one dividend mechanic for a stock where two issuers do it differently. That one is worse, because it is a specific false statement about what will happen to somebody's money.
The model has three levels because the thing being described has three levels.
What that looks like on the page
A stock appears exactly once, wherever it appears. NVDA existing seven times never means seven cards.
The issuer and the chain are printed on it as facts, rather than offered as a choice. There is no chain switcher standing between you and a stock, and no issuer selector you have to clear first. Chain is a facet, never a gate.
Under the stock, the instruments are rows. Each row names its issuer, in that issuer's own brand, and prints that issuer's wrapper and mechanic. Where an issuer has the same instrument on several chains, the addresses are listed under it rather than beside it.
Nothing is ranked. No issuer is preferred, no chain is suggested, and nothing is scored. Every ordered list on this site states what it is sorted by, because a ranked list is advice delivered by layout whatever the disclaimer underneath it says.
The part that is enforced by the code
The mechanics type is a discriminated union, which means a listing with no multiplier cannot render a multiplier field. Not "N/A", not "1.000000". The field is structurally absent, so the bug where a fabricated number fills a column cannot be written.
Same reason a flat price change shows a sector tag instead of "0.00%". A fake zero reads as "flat", which is a different claim from "we do not have this number".
Where to see it
Any stock with more than one issuer shows the shape immediately. NVDA is a good one. The issuers list is the middle level from the issuer's side, the chains matrix is the bottom level from the chain's side, and the glossary defines instrument, listing and wrapper.
If you are consuming our data rather than reading it, the same three levels are in the JSON API, and the shape is documented rather than implied.