What must be recognized if the sum of undiscounted future cash flows is less than the carrying amount of the asset under U.S. GAAP?

When the sum of undiscounted future cash flows from an asset is less than its carrying amount, it signals that the asset is not going to generate sufficient cash flows to recover its value on the balance sheet. Under U.S. GAAP, this situation triggers the necessity to recognize an impairment loss.

Specifically, the impairment test is designed to ensure that the carrying amount of the asset does not exceed its recoverable amount, which is usually the fair value of the asset. If the expected cash flows do not meet or exceed the asset's carrying amount, it indicates that the asset is worth less than what is recorded in the financial statements, essentially reflecting a loss in value that must be reported as an impairment loss on the income statement.

This loss ensures that the financial statements accurately reflect the current economic reality of the asset's value, maintaining the integrity of financial reporting. Thus, recognizing an impairment loss is essential for compliance with U.S. GAAP when the recoverable amount falls short of the asset's carrying amount.