By Lawrence Matheson NatWest, which also owns Royal Bank of Scotland, Ulster Bank and Coutts, is set to reveal its financial results for the last quarter and the full year on Friday. The bank is predicted to report a pre-tax profit of £6 billion for the year, with an income totalling £14.6 billion, according to analysts’ consensus from November. Investors were rattled in October when the bank lowered its forecast net interest margin (NIM) for the year, causing its share price to drop. The NIM shows the difference between what the bank pays out to savers and what it receives from interest on lo…