LONDON (Reuters) - South African investment banking and asset management group Investec reported a 15 percent rise in full-year core profit on Thursday, but missed expectations because of U.S. writedowns.

Pretax operating profit rose to 537.7 million pounds for the year to March 31, meaning growth was 3 percent lower than expected according to a Reuters poll.

The consensus forecast was 551 million pounds in pretax operating profit, according to Reuters Estimates.

Private banking, asset management and property divisions grew substantially. But profits at its investment banking division dropped 15 percent because of the credit crunch.

Overall the results were hit by writedowns in its U.S. Principal Finance division.

Adjusted earnings per share rose by 6.8 percent to 56.9 pence.

The board proposed a final dividend of 13.5p, bring the total annual dividend to 25p, a rise of 8.7 percent.