CG57690 - Unit trusts: valuation
The market value of units for which the managers regularly publish values is the ‘bid� price, TCGA92/S272 (5). This is the price at which the managers are prepared to buy units from unit holders. It will be lower than the ‘offer� price which is the price at which the managers agree to sell units. If prices were not published on the day for which you need a value use the value on latest day before.