"Mark to market basis": 1. In financial accounting, the recognition of assets and liabilities at their current market values, as at the end of the financial accounting period. 2. A basis of taxation which follows the mark to market basis of financial accounting. 3. UK tax. A method of allocating loan-related payments to the period in which they become due and payable and brings the value of loan relationships into account at fair value at the end of each period.