The objectives of Commonwealth Bank as the new owner of Bank of Western Australia may explain a large part of the drastic rise in bad-debt provisions for BankWest disclosed yesterday.CBA also needs to finalise acquisition accounting in a way most favourable to CBA as the buyer of BankWest, and, several newspapers report this morning, CBA plans to attempt to claw back somewhere between $200 million and $350 million of the purchase price paid to Lloyds TSB for BankWest back in December.The trading detail that it suited CBA and BankWest to publicise yesterday, in media releases, was the rise in the loan impairment to $825 million in the year to December 2008, up from $88 million in 2007.Financial statements filed with ASIC yesterday show BankWest impairment losses increased to $895 million in 2008 from $157 million the year before. The 2008 figure is equal to1.5 per cent of gross loans of $59 billion. Whether BankWest has a disproportionate share of bad commercial property loans and maybe a few sour mining and other business loans (the housing and consumer books cannot be the issue) is something Lloyds and CBA will now wrangle about. The BankWest provisions look on the high side compared with, say, Suncorp, which itself surprised the market with the level of its provisions.The emphasis on the surge in bad tends eclipsed the equally interesting detail that BankWest's operating profit before impairments and tax increased 62 per cent to $597 million, an underlying profit generated on the back of a 32 per cent increase in operating income.In its financial statements, BankWest attributed the income increase to "proactive repricing of the variable lending book" and a $121 million revaluation of securitisation notes.The financials show a statutory net loss of $139 million following a profit of $205 million in 2007. The brief commentary in the annual report does not deal with the east coast expansion where the bank now has about 45 outlets open (though only for an average of nine months).CBA tipped in $700 million in new capital to BankWest and refinanced $530 million in preference shares.