SYDNEY, AAP – Commonwealth Bank shares lost eight per cent and the Australian market fell for a second consecutive day.

The bank’s net interest margin has been slashed from low interest rates and investors sold the shares to close at $98.99 on Wednesday.

The big four banks were all lower, as were the biggest miners, which weighed on an otherwise upbeat market.

The benchmark S&P/ASX200 index closed down 50.5 points, or 0.68 per cent, to 7369.9 points.

The All Ordinaries closed lower by 43.1 points, or 0.56 per cent, to 7704 points.

The Australian dollar was buying 72.82 US cents at 1620 AEDT, lower from 73.57 US cents at Tuesday’s close.