what kind of risk there is if an ETF has very small valume?

Answer 1

ETF's are closed end unit investment trusts or closed end mutual funds. Other closed end funds often trade at a discount or premium. ETF sponsors work to keep that from happening in the ETF market, but there is no reason an ETF could not trade away from the market. It hasn't happened yet, but it probably will, just as there have been money market funds that have "broke the buck." It shouldn't happen, but there is no reason why it could not happen.

Additionally, illiquid investments are difficult to get out of. If volume is small, the market could move very far away from the original price while trying to get out.

Answer 2

ETFs are cheaper than mutual funds. ETFs have very low annual expenses, nearly 20 basis points or 0.2% less. As against this, actively managed mutual funds show average expenses exceeding 135 basis points (1.35%). This does not include the extra 2% - 5% as loads, 12(b)-1 marketing fees, transactions costs, and soft dollar expenses mutual funds, passed on to you but never informed, except in very fine print that nobody cares to read.
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