An investment fund is a supply of capital belonging to numerous investors used to collectively purchase securities while each investor retains ownership and control of his own shares https://www.investopedia.com/terms/i/investment-fund.asp 基金是不能让你频繁交易的，不同基金有不同的交易限制。基金一般每天收市后update一次value，不会实时update
除了盘前盘后交易，两者交易时间一样。基金每天不管啥时买卖，只有收盘时一个价格；股票实时交易，etf类似股票。