# S3 Short Interest Data

Revised short interest and three-sided borrow rates, delivered by contract only.

*https://stockmarketstack.com/tools/s3-partners · Insider, 13F & Congressional Trade Trackers*

## Facts

### At a glance

| Field | Value |
| --- | --- |
| Vendor | S3 Partners |
| Category | Insider, 13F & Congressional Trade Trackers |
| Job | short_interest |
| Website | https://www.s3partners.com |
| Pricing model | subscription |
| Free tier | false |
| Open source | false |
| Licence | none |
| Self-hosted | false |
| Tested hands-on | false |
| Last updated | 2026-09-21 |

### Pricing

| Tier | USD | Period |
| --- | --- | --- |
| Licensed dataset | on request | month |

### Coverage

| Field | Value |
| --- | --- |
| Asset classes | stocks, etf, bonds |
| Markets | global |
| Works outside the US | true |
| Data latency | delayed |
| Platforms | web |
| AI features | none |

### Interfaces

| Field | Value |
| --- | --- |
| API | true |
| Webhooks | false |
| Scripting | none |
| Python | false |
| Spreadsheet add-in | false |
| MCP server | false |
| Export | csv, api |

### Capabilities

Yes: none

No: charting, screening, scanning, backtesting, automation, live_trading, paper_trading, portfolio_tracking, broker_import, tax_reporting, alerts, news, options_analysis

*Verified: pricing 2026-09-21; capabilities 2026-09-21; coverage 2026-09-21.*

## What it is

The institutional standard for lending-derived short-interest data, and the one product in this
category a private investor cannot buy.

S3 computes what it calls revised short interest from custody data, prime-broker inventory feeds,
regulatory filings and exchange data, with an in-house desk confirming rates from the voice-brokered
financing market. The pitch is not that this supplements the exchanges' twice-monthly figure but
that it replaces it.

The distinctive field is the borrow rate, and S3 is alone in publishing three of them: the offer
rate a borrower pays, the bid rate custody banks charge prime brokerage, and the last rate for new
shares. On top sit utilization, indicative availability, days to cover over 10, 30 and 90-day
windows, and proprietary crowding, squeeze-risk and short-momentum scores plus a market-wide
mark-to-market of short P&L net of borrow cost.

## Pricing

Nothing is published. The AWS Data Exchange listing states that institutional pricing varies with
the number of users in the enterprise; the vendor's trial page says data trials are complimentary
and gives no duration; every other route ends at a sales address or a phone number.

One oddity, recorded rather than relied on: the same AWS Data Exchange listing that describes
variable institutional pricing also carries a zero-cost subscription line with no end date. The two
statements sit on one page and this card cannot reconcile them without subscribing. Do not plan
around S3 data being free.

## Data & coverage

Global — equities, ETFs and funds, corporate and government bonds, ADRs — with history since 2015.
The security count is the one number to take with care: the AWS listing says more than 70,400, the
product page says 65,000-plus and the company boilerplate says more than 50,000. Three figures for
one dataset, all the vendor's own.

Updates are hourly on the feed specification: a start-of-day file at 08:00 ET and hourly refreshes
from 09:00 to 17:00 ET. Fails-to-deliver is not among the datasets. The official FINRA and exchange
figures are used as an input rather than sold as a product.

History is explicitly not point-in-time, which the vendor documents plainly. A revised series
restates what it previously published, so anything backtested against it is testing on numbers that
were not visible on the day.

## Limitations

- **There is no way for an individual to buy it.** No price, no self-serve, and the retail channel
  is out of service.
- **Not point-in-time.** Disqualifying for a study that needs to know what was knowable then.
- **Delivery is through somebody else's platform.** Bloomberg, FactSet, Marquee, Snowflake or a
  file drop; the direct API has no public documentation, no published limits and no way in without
  a contract.
- **Three security counts in the vendor's own material,** and an update frequency that reads as
  real-time in marketing and hourly in the spec.
- **No fails-to-deliver,** and no insider or ownership data of any kind.

## Alternatives

[ORTEX](https://stockmarketstack.com/tools/ortex) is the self-serve competitor on the same idea — a lending-pool estimate with
published prices from $39 a month and an API. [ChartExchange](https://stockmarketstack.com/tools/chartexchange) sells the
official filings, one broker's borrow fee and fails-to-deliver from $19.95 a month.
[iBorrowDesk](https://stockmarketstack.com/tools/iborrowdesk) covers borrow fees free. For short interest inside an ownership
product, [Fintel](https://stockmarketstack.com/tools/fintel). The rest of the category is at
[insider, 13F and congressional trade trackers](https://stockmarketstack.com/categories/insider-13f-trackers).

## FAQ

### Can an individual buy S3 data?

Not today, as far as this card can establish. There is no self-serve purchase path, no published price and no retail product in service — the ShortSight site that was S3's retail channel returned a Cloudflare origin error when checked on 21 September 2026, although its support address is still printed on S3's AWS Data Exchange listing.

### How is this different from the official short interest?

S3 presents its figure as a replacement rather than a supplement, calling it revised short interest. It is built from custody data, prime-broker inventory, regulatory filings and exchange data, with a desk confirming voice-brokered financing rates, and it is published far more often than the exchanges' twice-monthly filing.

### How often does the data update?

The feed specification says hourly — a start-of-day file at 08:00 ET and then hourly updates from 09:00 to 17:00 ET — while the marketing copy says real-time and the product page says daily. Hourly is the number to plan against, because it is the one in the delivery spec.

### Is the history point-in-time?

No, and S3 says so in its own documentation. That matters for anyone backtesting against it — a revised series restates the past, so a study run over it can see numbers that were not available on the day.

### How is it delivered?

Through other people's platforms, mostly. Bloomberg as a terminal app and through BQL formulas, plus Black App Web, Goldman Sachs Marquee, FactSet, LSEG, Snowflake, SS&C Eze, Omega Point, AWS Data Exchange as CSV, SFTP, and a direct API with no public documentation.

## Also worth comparing

- [ChartExchange](https://stockmarketstack.com/tools/chartexchange.md) — The official short interest, IBKR's borrow fee and SEC fails, sold feature by feature.
- [Fintel](https://stockmarketstack.com/tools/fintel.md) — Ownership, insider and short-interest filings across thirty markets, none of it free.
- [iBorrowDesk](https://stockmarketstack.com/tools/iborrowdesk.md) — Interactive Brokers' borrow fees and availability, free, refreshed through the day.
- [ORTEX](https://stockmarketstack.com/tools/ortex.md) — Short interest estimated daily from the lending pool, with cost to borrow beside it.
- [HedgeFollow](https://stockmarketstack.com/tools/hedgefollow.md) — 13F, Form 4 and congressional filings from 10,000 funds, with the depth behind a paywall.
- [Quiver Quantitative](https://stockmarketstack.com/tools/quiver-quantitative.md) — US political and SEC disclosure data — congress, insiders, lobbying — over one REST API.