Investors can look forward to reports of earnings growth of between 10 and 20 per cent from three of the big four banks reporting their 2010/11 financial results over the next two weeks. But the outlook for the 2001/12 year is far less certain and investors will be looking for guidance as to what to expect over the coming 12 months.Analysts' consensus forecast for National Australia Bank's result, which will be announced on Thursday, is for a 20 per cent increase in cash earnings, from A$4.5 billion last financial year to $5.4 billion for the year to September.Westpac and ANZ report next week. The consensus forecast for ANZ is for an increase in cash earnings of 9.8 per cent, from $5.1 billion last year to $5.6 billion for the year to September.The consensus forecast for Westpac is for a 12 per cent increase, from $5.9 billion to $6.6 billion.The majority of analysts are expecting subdued conditions in 2011/12. This view was summed up in a report issued earlier this month by Citi's banking analyst, Craig Williams, who said the outlook for growth in Australian bank earnings has been cut back sharply because of the impact of the slowing global economy. Williams' forecast is for earnings per share growth in 2011/12 of zero to two per cent. This low growth scenario is based on forecast credit growth for the year ahead of just 4.5 per cent. Williams is also expecting loan impairments to rise. "Citi has lifted its bad debt estimates by around 30 to 40 per cent for 2011/12. It expects that losses will come from commercial property companies and other small corporate customers."The countervailing view is summed up in a Deutsche Bank report earlier this month, which said: "Consensus revenue growth forecasts are too low. We can see margin expansion of 4.5 basis points per annum, driven by strong deposit growth and falling wholesale funding requirements." Deutsche said stronger deposit growth usually comes with lower lending growth. This helps lower the cost of funds and aids margins.Banks are competing less for deposits, and spreads on term deposits and at-call accounts are coming in.  "The deposit story is the key area of upside," Deutsche saidIt said: "Coupled with good non-interest income growth, as wealth management and markets' divisions rebound from depressed levels, this points to revenue growth of around seven per cent."