Short interest tracks shares that have been sold short and have not yet been bought back. When short interest rises, the reported open short position has increased. When it falls, the reported open short position has decreased.
The number is most useful as a trend. A single report can be noisy, but a series of reports can show whether short positioning has been building, easing, or staying relatively stable.
Current short interest is the latest reported open short position. Prior short interest is the previous report’s value. Change shows the difference between the two. Days to cover compares short interest with average daily volume.
Short interest does not explain why traders are short a stock. It also does not predict price direction by itself. A large short position can reflect negative views, hedging, arbitrage, or other strategies.