Commonwealth Bank of Australia has launched a $5 billion rights issue to boost capital in response to regulatory pressure and has posted a full-year cash profit of $9.14 billion, up 5 per cent and the largest-ever profit by an Australian bank. CBA shares are in a trading halt ahead of the raising, which will boost CBA's closely watched common equity tier 1 capital ratio to 10.4 per cent, lifting it back to the top of the big bank pack.