The basis upon which personal income or business profits are assessed in the UK for each fiscal year. The individual rules for each income-tax schedule identify the profits or income to be assessed in that year. These rules are complex and the advice of a tax expert should be sought. The basis of assessment does not necessarily equate to the actual tax year. In the case of a partnership that has been trading for many years, the profits for the year to 30 April 2010, i.e. those arising during the period 1 May 2009 to 30 April 2010, will form the basis of the assessment for the tax year 2010–11. This is known as the current-year basis of assessment. Other income received during the year, e.g. building society interest received, is assessed on an actual basis and so for 2010–11 the basis of assessment will be the tax year, i.e. the interest received during the year 6 April 2010 to 5 April 2011.