The ratings agency said the risk for banks with large capital market operations has increased and is unlikely to subside in the medium term.
Risks cited include volatile global markets, the eurozone crisis and the uncertainty surrounding tapering of QE in the US.
Creditworthiness was called into question at Deutsche due to its questionable ability to generate stable and predictable revenues, Credit Suisse was deemed to have earnings volatility and Barclays is said to have a relatively high investment banking weighting.
In its update on Deutsche, S&P said: “We see the new US banking rules on leverage as the most penalising for the bank, possibly reducing the volume of US transactions such as reverse repos. The new rules may also translate into higher fund costs for Deutsche Bank’s US subsidiaries, weakening profitability.”
S&P rates the outlook for all three banks as stable, but an upgrade for both Deutsche and Barclays in the next two years was a remote possibility.
Barclays and Deutsche declined to comment on the matter.
Last year fellow ratings agency Moodys downgraded 15 banks in one fell swoop.
