Equity and fixed income funds play an important role for the impressive Thai mutual fund growth. With an in depth analysis, we found two major facts. Firstly, Thai mutual fund industry is concentrated in fixed income mutual funds especially short-term money market funds. Secondly, approximately 50% of the AUM invested in Thai equity mutual funds are from LTF and RMF or growth in equity mutual funds is affected by tax incentive. Further in depth analysis aiming at indicating reasons of product concentration on fixed income funds and how tax incentive help increase AUM of equity funds is performed by categorizing.