Westpac's attempt to justify its out-of-cycle mortgage rate rises could be fatally undermined by a raft of earnings upgrades from investment analysts in the next 48 hours.Preliminary analysis by Goldman Sachs analyst Andrew Lyons indicates that the 14 basis point increases on owner-occupier and investor mortgages could boost the bank's cash earnings in 2019 by more than A$300 million.Lyons told clients in a research note last night that the rises could drive up annual cash earnings by around 4 per cent and add six bps to the group's net interest margin.Westpac generated cash earnings of more than A$8 billion last year and currently enjoys a sector-leading net interest margin of 2.1 per cent.The widely expected earnings upgrades loom as reputational poison for the bank after the head of its consumer banking operations George Frazis suggested the rate rises would not recoup higher funding costs borne by the bank in the last six months."We initially hoped that this increase would be temporary, and therefore we have incurred these costs over the last six months," Frazis said on Wednesday."The rate changes announced today will not recover these costs."This claim will be tough to sell to federal politicians and the Australian public if more analysts signal that the rate rises will add two-or-three hundred million dollars to Westpac's cash profit.The rate rises will not take effect until the second last week of September, which means they are likely to have only a small impact on the bank's earnings in the current year.Lyons has delayed formally upgrading his earnings estimates pending the strategic responses of the other three major banks to Westpac's repricing."In isolation, today's 14 basis point increase across all of Westpac's Australian variable mortgage rate products would increase its group net interest margin by circa six basis points and increase cash earnings by circa 4 per cent," Lyons told clients in the research note."We will await the response from Westpac's major bank peers before including this impact in our forecasts, so we can also assess any potential market share implications in our forecasting."However, we do highlight that, despite the ongoing Royal Commission, the ACCC investigation into mortgage pricing and political focus on the sector, today's Westpac announcement confirms our view that bank pricing power in the face of higher input (and) funding costs has not been adversely diminished."