The primary trading difference between Exchange-Traded Funds (ETFs) and mutual funds is their liquidity and pricing mechanism. ETFs are listed on a stock exchange and can be bought and sold throughout the trading day at fluctuating market prices, similar to individual stocks. In contrast, index mutual funds, like all mutual funds, are priced only once per day after the market closes, at their Net Asset Value Per Share (NAVPS). All purchase and redemption orders for the day are processed at that single price.

A. Both ETFs and index mutual funds are subject to tracking error, which is the deviation between the fund's performance and the index it is designed to track.

C. The market price of an ETF can deviate from its underlying net asset value (NAV) due to supply and demand, trading at a premium or a discount.

D. ETFs do have management fees and operating expenses, which are combined into a Management Expense Ratio (MER), although it is often lower than for mutual funds.

- Canadian Securities Institute. (2022). Investment Funds in Canada (IFC). Chapter 4: Exchange-Traded Funds, Section "Comparing ETFs and Mutual Funds", pp. 4-12 to 4-14. The text explicitly contrasts the intraday trading of ETFs with the end-of-day pricing of mutual funds.

- CFA Institute. (2020). Investment Products and Asset Classes. In CFA Program Curriculum Level I (Vol. 5, Reading 39). The curriculum details how ETFs trade on exchanges with continuous pricing, while open-end mutual funds transact at the end-of-day NAV.