ChartExchange

What it is

A US short-side data site that grew out of the 2020 retail boom and turned into something more useful than that origin suggests: four distinct short-related datasets, each served on a symbol page and through a documented REST API, priced à la carte rather than as plans.

The four are worth separating, because most products here carry one of them and describe it as "short interest".

The official filing. FINRA's semi-monthly short interest, with days to cover computed against average daily volume. This is the number the exchanges publish and the one everything else is measured against.

A daily short-interest series. Same field schema, published daily. ChartExchange does not say where it comes from or how it is derived, and it sits behind the paid tier. That silence is the single most important thing to know about this product.

Interactive Brokers' cost to borrow, labelled as exactly that — one broker's rates, timestamped and queryable intraday.

SEC fails-to-deliver, re-served with fields the SEC's own file does not carry: the trade date, that date plus 35 calendar days, the notional value, and split adjustment.

Alongside them sit daily off-exchange and per-venue short volume from the Reg SHO files, dark-pool levels and prints, an options tape sold separately, and screeners for high short interest and high borrow fee.

Pricing

Features, not plans, on monthly, quarterly and annual billing with roughly 8 and 17 per cent off the longer terms.

The entry point that matters is Investor at $19.95 a month, which unlocks extended history, real-time prices, exports, dark-pool detail and the daily short-interest series. API access starts at $29.95 and includes Investor rather than stacking on top of it, which makes Tier 1 the sensible first purchase for anyone who wants both. Above that, $49.50 and $89.65 buy rate limit and nothing else — 60, 250 and 1,000 requests a minute.

Everything except the ad-free Supporter add-on carries a fourteen-day trial.

Data & coverage

US equities and ETFs only, with an options tape for the same market. Short interest back to 2018, Interactive Brokers' borrow fee back to 2016, fails-to-deliver back to 2004 and short volume back to 2017 — deeper history than the price suggests, and the reason to prefer this over scraping the regulators' files yourself.

Everything here is a regulator's file or one broker's book, republished with derived fields on top. There is no estimate of true short interest from lending inventory, which is what ORTEX and S3 sell and what costs an order of magnitude more. The exception is the undocumented daily series, which is either a fifth dataset or a derivation, and the site does not say which.

Integrations

REST with the key in the query string, JSON or CSV output, pages of up to 1,000 rows, and an OpenAPI schema that carries its own changelog. No websocket, no MCP server, no spreadsheet add-in, no Python SDK. The API rejects unauthenticated calls, so there is no anonymous tier to test against.

Limitations

• The daily short-interest series has no published source. For a paid dataset that reads like a headline figure, that is a gap a buyer should not paper over.
• Cost to borrow is one broker's. Interactive Brokers is a reasonable proxy and it is not the market.
• US only, on every dataset.
• The free history window is unstated, so what the $19.95 actually extends is unclear until you pay.
• No alerts, no MCP, no SDK. This is a data source and a website, not a workflow tool.
• Small vendor, no institutional terms published. Redistribution is not addressed anywhere in the pricing material.

Alternatives

ORTEX is the estimate-driven competitor at three to five times the price, with intraday short interest, cost to borrow across the whole lending pool and an MCP server. iBorrowDesk gives the same broker's borrow fee free. S3 Partners is the institutional version, contract-priced. Fintel folds short interest into ownership and insider data across thirty-odd markets from $7.95 a month billed annually. The rest of the category is at insider, 13F and congressional trade trackers.