Bank investors hoping that the upcoming profit season might trigger a re-rating of the ASX's most out-of-favour sector are likely to be disappointed as margin pressure, cost blowouts and regulatory uncertainty compress the earnings outlook for the industry.That's the shared view of most leading bank analysts, who say the era of sustained returns on equity above 15 per cent are now an item of history."Going forward, I think earnings per share growth across the sector is going to slow," said CLSA chief banking analyst, Brian Johnson."The slowing earnings trend is due to a combination of factors including the enforced switch of borrowers from interest-only to P&I loans, normalising financial markets, non-recurrence of writebacks and rising remediation, technology and regulatory costs."ANZ kicks off the annual reporting season on Wednesday morning and is expected - according to Bloomberg consensus forecasts - to report a 7 per cent decline in full year cash profit from continuing operations to $6.374 billion.The reported net profit is expected to fall by around 5 per cent to $6.05 billion.ANZ's lending operations lost momentum in the September half, with APRA data showing that mortgage volumes slowed to 0.3 times the system growth rate in the five months to the end of August.Chief executive Shayne Elliott will be under pressure to explain the reasons for the bank's underperformance in home lending and to articulate the group's strategy for retrieving market share."We would be interested in management commentary on the outlook for mortgage volume growth and to what extent the current softness has related to serviceability changes through the business, slower customer demand or specific management actions reflecting concern around the state of the housing market," said Goldman Sachs analyst, Andrew Lyons.There is an emerging view among analysts that dividends could be chopped across the major banks some time over the next 12 months, but the consensus outlook is that ANZ will maintain the 2018 final dividend at 80 cents per share.Pressure is mounting on the board to cut dividends because of the earnings runoff in the Australian banking business.Several analysts think the bank will report a large slide in diluted earnings per share - as much as 15 cents to $2.07.This would raise the dividend payout ratio to around 74 per cent and leave the bank with less fresh capital to tap for its ambitious digital transformation program.While other banks, particularly NAB, will be forced to issue more scrip to meet APRA's new 10.5 per cent requirement for tier one capital, ANZ is already compliant with the new standard.However, investors will be seeking guidance from the company on whether the steeper regulatory capital benchmark will reduce the bank's ability to expand share buyback activity.