Net Asset Value(s)

3 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 £63.0 million. Income Shares * 60.82p Capital Shares 0.00p Zero Dividend Preference Shares 56.79p Income & Growth Units 60.82p Package Units 117.61p 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 56.49p. ---END OF MESSAGE---