Investec has downgraded its ratings for banking peer HSBC and RBS from 'buy' to 'hold' in separate research reports, reiterating its preference for rival Barclays.HSBCAnalyst Ian Gordon said that while HSBC is not overtly expensive, consensus forecasts for the dividend have "now caught up with our own (positive) view, whereas we regard the market's earnings expectations as still a little frothy".Investec is expecting the firm to report a pre-tax profit of $5.9bn for its second quarter, some 5.0% below the consensus estimate of $6.2bn.Gordon said: "To the extent that we are wrong, we expect Global Banking & Markets to get HSBC 'over the line'. We remain more confident that the market still has downgrades to both the net interest margin and net interest income to factor in."He pointed out that the stock has marginally outperformed the FTSE 100 so far this year and now trades within just 4.0% of its 57-month high.The 740p target price for HSBC has been maintained.RBSFollowing an impressive share price recovery after the stock was "oversold" in June (according to Gordon), RBS is now trading on 0.75 times 2013 tangible net asset value, "which we no longer regard as absurdly cheap - just cheap, and (perhaps) for good reason".The analyst believes that the main reasons for the initial sell-off - the removal of frontman Stephen Hester and the potential of an "ill-conceived" 'good bank'/'bad bank' split - still remain unresolved."However, we caution against adopting any aggressively negative stance on RBS. Constructive near-term solutions are at hand. If the Board were to act decisively and appoint Ross McEwan, who would be our top pick, within the next few weeks, we believe it would help to remove significant strategic uncertainty and perhaps convince shareholders that their interests will be protected."After raising his target price from 335p to 340p due to a strongly recovering UK mortgage market, Gordon said it implies little upside to current prices.BC