AMP Bank increased its contribution to group earnings by 16 per cent in the June half, despite a mixed performance. The group had strong deposit inflow but its home loan book shrank.AMP yesterday announced its results for the six months to June and reported that the banking division contributed operating earnings of $21 million in the six months to June, up from $18 million in the June half last year. The group made underlying earnings of $383 millionThe mortgage book was $9.8 billion at the end of June, down 0.1 per cent over the past six months. The bank wrote $763 million of mortgages in the June half, down from $988 million in the previous corresponding period.The net interest margin fell from 1.44 to 1.33 per cent. The bank made specific provisions of $1 million. Weighted average loan to valuation ratio was 54 per cent. Arrears (overdue 90 days or more) were 0.34 per cent, down from 0.49 per cent in the June half last year. Deposits were up nine per cent. The bank has $6.7 billion of balance sheet funding. The mix is 38 per cent retail deposits, 26 per cent superannuation deposits and 36 per cent wholesale deposits. It has $3.9 billion of off-balance sheet funding.