Propounding a Model for Portfolio Selection in Stock Exchange by Using of MCDM (Case Study: 50 Better Companies)

Decision making about the selection of shares for buying and selling for more return acquisition is the most important subject for investors in stock exchange market. Many of investors buy shares based on market gossips and informal news.As each of the existing models such as technical method, fundamental method, Markowitz model, sharp model and arbitrage model has it's own problem in use, this research gives a model for choosing portfolio regarding effective indices on investors decision making by composing the TOPSIS and GAHP techniques. A questionnaire was prepared by using Delphi method and was distributed to 30 persons of the experts of stock exchange market to identify significant indices for investors. Economical indices for choosing the industry including selling growth, profit margin growth, average return, currency rate, basic metals price volatility, industrial competitive advantages, economical growth and recession and economical indices for share selection contain EPS, DPS, P/E, share price, share return, operating profit ratio, corporation management, corporation size, capital volume and technology were achieved.Necessary information and relevant amounts to each of indices were gathered from archive unit and internet site of securities and exchange organization and financial statement of companies. Then by TOPSIS technique and weighting by Shannon entropy and group AHP techniques in changing qualitative to quantitative indices (which is one of the most advantages of this method) decision matrix was composed and the priority of industry and share identified. Five superior industries were Banking, Credit and other money institutes, Investment brokers, Foods and Beverages products except candy and sugar, coal extraction and Other Nonmetallic mineral products.