Australia Finding original cost of assets from fair value accounts

[maccua]

I have developed this formula for determining original cost of assets of an investment company that uses fair value accounting:

originalCost = bookValue-unrealizedGainLossLess12Month-otherComprehensiveIncome

where bookValue is the fair value of assets reported on the balance sheet, unrealizedGainLossLess12Month are unrealized gains and losses are for securities held for trading (within 12 months) reported on the income statement. OtherComprehensiveIncome includes unrealized gains and losses on securities available for sale, which is accumulated on a separate line of the balance sheet.

Does this look right? Thanks for any validation, insights, alternative viewpoints...

maccua