when open interest increases it usually means new money is coming into the market for that option as long as this is happening the current trend will continue when open interest decreases it is usually a sign that the market is liquidating and more investors are leaving this often means that the current price trend is ending 
the bottom lineopen interest is the total number of open derivative contracts that haven t been settled they haven t been exercised closed out or expired this measurement is associated with the options and futures market rather than the stock market open interest is equal to the total number of open contracts not the sum of all transactions between buyers and sellers 