ABSTRACT : Choosinginvestments can indeedbedifficult for investors, especially in uncertain times. Investorswill face number of considerationsthatwill impact future investmentresults, and it all depends on how investorsbehavewhenmakinganinvestmentdecision. However, investorsoccasionallymakebiased or irrationalinvestmentdecisions, whichcouldresult in bothmaterial and immateriallosses or undesirableoutcomes in theirinvestmentactivities. The aim of thisstudywas to investigate the impact of herdbehavior and heuristicsuch as anchoring, representativeness, availability, overconfidence, and gambler’sfallacy on investmentdecisionmaking of investors in Malang City. This study’ssampleconsist of investors in Malang city whomeet a number of predeterminedcriteria. Multiple regressionanalysisisused in thisstudy to test the data. According to the study’sfindings, herdbehavior, anchoring, representativeness, availability, overconfidence, and gambler’sfallacy all have a positive impact on investmentdecisionmaking of investors in Malang City. This demonstratedthatinvestors in Malang City occasionallymakedecisionsbased on irrationalthinking, which has a negative impact on theirinvestment return.

KEYWORDS -Herd Behavior, Anchoring, Representativeness, Availability, Overconfidence, Gambler’s Fallacy