The accounting for investments occurs when funds are paid for an investment instrument. The exact type of accounting depends on the intent of the investor and the proportional size of the investment. Depending on these factors, the following types of accounting may apply:
Held to maturity investment. If the investor intends to hold an investment to its maturity date (which effectively limits this accounting method to debt instruments) and has the ability to do so, the investment is classified as held to maturity. This investment is initially recorded at cost, with amortization adjustments thereafter to reflect any premium or discount at which it was purchased. The investment may also be written down to reflect any permanent impairments. There is no ongoing adjustment to market value for this type of investment. This approach cannot be applied to equity instruments, since they have no maturity date.
Trading security. If the investor intends to sell its investment in the short-term for a profit, the investment is classified as a trading security. This investment is initially recorded at cost. At the end of each subsequent accounting period, adjust the recorded investment to its fair value as of the end of the period. Any unrealized holding gains and losses are to be recorded in operating income. This investment can be either a debt or equity instrument.
Available for sale. This is an investment that cannot be categorized as a held to maturity or trading security. This investment is initially recorded at cost. At the end of each subsequent accounting period, adjust the recorded investment to its fair value as of the end of the period. Any unrealized holding gains and losses are to be recorded in other comprehensive income until they have been sold.
Equity method. If the investor has significant operating or financial control over the investee (generally considered to be at least a 20% interest), the equity method should be used. This investment is initially recorded at cost. In subsequent periods, the investor recognizes its share of the profits and losses of the investee, after intra-entity profits and losses have been deducted. Also, if the investee issues dividends to the investor, the dividends are deducted from the investor's investment in the investee.
An important concept in the accounting for investments is whether a gain or loss has been realized. A realized gain is achieved by the sale of an investment, as is a realized loss. Conversely, an unrealized gain or loss is associated with a change in the fair value of an investment that is still owned by the investor.
There are other circumstances than the outright sale of an investment that are considered realized losses. When this happens, a realized loss is recognized in the income statement and the carrying amount of the investment is written down by a corresponding amount. For example, when there is a permanent loss on a held security, the entire amount of the loss is considered a realized loss, and is written off. A permanent loss is typically related to the bankruptcy or liquidity problems of an investee.
An unrealized gain or loss is not subject to immediate taxation. This gain or loss is only recognized for tax purposes when it is realized through the sale of the underlying security. This means that there may be a difference between the tax basis of securities and their carrying amount in the accounting records of the investor, which is considered a temporary difference.