First, when the liquidity of ETFs is not very good, there are actually many ETFs with poor liquidity in the market, and the actual transaction price will deviate more from IOPV.
Second, when the market is extreme, such as when the index rises or falls sharply, the constituent stocks will have a large-scale daily limit or daily limit. When there is a daily limit, ETF will have a premium. The principle is that everyone will grab the ETF share. At this time, because the stock can't be bought at the daily limit, there will be an ETF premium. On the other hand, if the constituent stocks fall in a large area, then the ETF will have a discount.
Third, ETFs that usually exist in some illiquid primary and secondary markets, such as QDII ETFs, usually use QDII quotas to invest in overseas stocks. In this case, due to the limit of quota, the primary and secondary markets cannot arbitrage through normal channels, and ETF will have a large discount premium.
What are the risks of ETF?
ETFs are more worry-free than ordinary Public Offering of Fund, because ETFs can be traded on the floor, so you should pay attention to IOPV at the right time, and don't buy at a high premium or sell at a low discount. When the transaction price in the secondary market deviates from IOPV, there are usually some tricks, so pay special attention at this time.
Etfs, like stocks, should calculate their positions and pay attention to the quantity and price when placing orders. Occasionally, ETFs temporarily suspend trading for the same period of time as stocks, making it impossible to trade. This kind of situation is generally less.