What is the major difference in the accounting for a portfolio of trading securities and a portfolio

Question:

What is the major difference in the accounting for a of trading securities and a of available-for-sale securities?

Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...