This page tracks how heavily Perma-Fix Environmental Services (Nasdaq:PESI) is being shorted: ORTEX's daily short interest estimate, the cost to borrow the shares, utilization of the lendable supply and days to cover, next to the official exchange-reported figure.

Short interest

The number of shares that have been sold short and not yet bought back, usually shown as a percentage of free float (the shares available to trade). ORTEX estimates it every day from securities-lending data, instead of waiting for exchange reports that are published only twice a month and about two weeks late.

Cost to borrow

The annualised fee a short seller pays to borrow the shares, as a percentage of the position's value. A rising cost to borrow means lendable shares are getting scarce and holding the short is getting more expensive.

Utilization

The share of the lendable supply of a stock that is currently on loan. Close to 100% means almost no shares are left to borrow.

Days to cover

Short interest divided by average daily trading volume: roughly how many days of normal trading it would take for every short seller to buy back their shares.

Exchange-reported short interest

The official figure published by the exchange or regulator (in the US, FINRA twice a month). It is accurate but delayed, which is the gap the ORTEX daily and intraday estimates fill.

Source: ORTEX. Some figures are limited on the free view; live data and full history are part of ORTEX Advanced.

PESI key data

Perma-Fix Environmental Services (Nasdaq: PESI) has a market capitalization of $338.32M. Last close $15.93 (as of 2026-11-12); 52-week range $8.58 to $21.32. ORTEX data as of 2026-10-27: short interest was 18.14% of free float, 12 days to cover and the average cost to borrow was 0.74%. Sign up for live short interest data.

About this data: PESI short interest, cost to borrow and days to cover