What is short interest reporting? FINRA guide (2026)

Short interest reporting is the twice-monthly record of how many shares are sold short and still open in a given equity security. In the United States it runs under FINRA Rule 4560: member firms report the open short positions in all customer and proprietary accounts, FINRA compiles them by security, and publishes the totals. It is the only regular, public, security-level view of the short side of the US market. This guide explains what short interest reporting is, the schedule it runs on, and the four things it does not tell you. It is not investment advice.

How does short interest reporting work?

Short interest reporting has three steps, and each one carries a fixed deadline:

1. A settlement date is designated. FINRA sets two reporting settlement dates a month: the 15th of the month, or the previous business day where the 15th is not a settlement date, and the last business day of the month.
2. Firms report. Member firms must submit their open short positions by 6 p.m. Eastern Time on the second business day after the reporting settlement date.
3. FINRA publishes. The compiled data goes out on the seventh business day after the reporting settlement date, covering every equity security, with roughly five rolling years of history available as a downloadable file and through an API.

The reported figure is a snapshot of open positions at a moment, not a measure of activity over the period. It counts what was still open when the shutter closed.

What short interest reporting does not tell you

Four limits matter more than the headline number, and each one is structural rather than a gap someone forgot to fill:

• No names. The data is compiled per security across all reporting firms. Unlike a Form 13F, which names the manager against each long position, short interest identifies nobody.
• Positions sit with the broker, not the client. A firm reports the short positions carried in its accounts. The manager who actually put the trade on is invisible, and one manager's position can be spread across several firms.
• Round trips vanish. A short opened after one settlement date and covered before the next never appears. The record has holes by construction, not by accident.
• Age. By the time a figure publishes it describes a market state at least seven business days old, and up to three weeks old by the time the next one lands.

Where short interest sits among ownership disclosures

Most public ownership data is long-only. Form 13F reports the long US equity book of managers above the $100 million threshold. Forms 3, 4 and 5 report insider transactions. Form 13H identifies large traders without publishing their positions. None of them cover the short side, which is why FINRA's compiled figure has carried that whole question on its own.

That is set to change, though not soon. The SEC adopted Rule 13f-2 and Form SHO on 13 October 2023 to collect manager-level short positions, and after litigation and a series of extensions the first Form SHO filings are now due on 14 February 2028. For what that rule will add, and what it still will not disclose, see what is Form SHO and the side-by-side in Form SHO vs short interest report.

One change may land sooner. FINRA has filed a proposed rule change with the SEC to increase the frequency and granularity of the short interest it collects and disseminates, alongside a new rule on allocations of fail-to-deliver positions. The SEC designated 14 August 2026 as the date by which it must approve or disapprove it. That decision falls shortly after this post was published, so check the current position before relying on the twice-monthly schedule described above.

Reading short interest reporting alongside the filings

Short interest reporting answers one question well: how many shares in this security were sold short and still open on a given settlement date. It does not say who, why, or whether the position survived the week. Read next to the dated long-side record in shareholding patterns and 13F filings, it fills in a side of the register that is otherwise blank. Flock reads disclosure filings and keeps each one dated and linked to its source. What any of it means for your money is your call to make.