Issuing a note of caution in mutual funds' debt investment, SEBI Chairman Ajay Tyagi on Thursday said mutual fund managers need to be vigilant while holding debt instruments and should appropriately\u00a0value the credit risk in their books. Speaking at the Association of Mutual Funds of India (AMFI) Summit, Tyagi said mutual fund managers have to be cautious of credit risk even as a bulk of the money comes from institutional investors, with almost Rs 11.5 trillion funds coming from non-retail investors out of total Rs 12.3 trillion assets under management (AUMs) at debt funds. While mutual funds have become an important element of the Indian financial system, one of the major concerns that remain in the industry is the concentration of mutual fund assets with only a few top asset management companies (AMC), said Tyagi. To address the concern of concentration of market share in hands of only a few, the SEBI chief called out for\u00a0healthy competition in the mutual fund space. "From an overall industry perspective, an industry which is growing and which is likely to grow much more, some thinking perhaps is required to bring in elements that facilitate healthy competition in the industry, which we feel is lacking as of now," Tyagi said. The chief of the country's market regulator on Thursday said that AUMs have more than doubled in the last four years and the number of folios has increased 27% over the past one year, from 5.99 crore to 7.59 crore in July 2018. Despite such growth, Tyagi said AUMs in the Indian mutual fund industry are just 11% of GDP as compared to the global average of 62%. "The fund industry in India has a lot of catching up to do and there are a lot of opportunities for the growth," said Tyagi. "It is a cause of concern that despite such tremendous growth majority of market share of the industry remain concentrated in a few big players. The top four mutual funds account for almost 50% industry aum and top 7 MFS account for around 70% of industry AUM," Tyagi said. "Concentration in the industry is evident not only in the AUM figures but also in the revenue and profit margins of MFs. It is absurd that share of revenue of 7 large AMCs is more than 60% of the total industry revenue," he added.