Net Asset Value(s)

8 October 2008 M&G High Income Investment Trust P.L.C. The Board of M&G High Income Investment Trust P.L.C. announce that the net asset value at 12:00 noon today was £59.8 million. Income Shares * 54.97p Capital Shares 0.00p Zero Dividend Preference Shares 56.79p Income & Growth Units 54.97p Package Units 111.76p The net asset values have been calculated on a cum-income basis, with dividends payable deducted from net assets on the ex-dividend date. Financial assets are valued on a mid-market price basis. * The ex-income NAV of each Income Shares is 50.59p. ---END OF MESSAGE---