what is the arms index trin 
the arms index also called the short term trading index trin is a technical analysis indicator that compares the number of advancing and declining stocks ad ratio to advancing and declining volume ad volume it s used to gauge overall market sentiment richard w arms jr invented the trin in 1967 and it measures the relationship between market supply and demand it serves as a predictor of future price movements in the market primarily on an intraday basis it does this by generating overbought and oversold levels which indicate when the index and the majority of stocks in it will change direction image by sabrina jiang investopedia 2021formula for arms index trin trin advancing stocks declining stocksadvancing volume declining volumewhere advancing stocks number of stocks that are higheron the daydeclining stocks number of stocks that are loweron the dayadvancing volume total volume of all advancingstocksdeclining volume total volume of all decliningstocks begin aligned text trin frac text advancing stocks declining stocks text advancing volume declining volume textbf where begin aligned text advancing stocks text number of stocks that are higher text on the day end aligned begin aligned text declining stocks text number of stocks that are lower text on the day end aligned begin aligned text advancing volume text total volume of all advancing text stocks end aligned begin aligned text declining volume text total volume of all declining text stocks end aligned end aligned trin advancing volume declining volumeadvancing stocks declining stocks where advancing stocks number of stocks that are higheron the day declining stocks number of stocks that are loweron the day advancing volume total volume of all advancingstocks declining volume total volume of all decliningstocks 