Moody's and Standard & Poor's lowered their rating of Barclays' outlook yesterday due to the Libor-rigging scandal.
The ratings agencies cited "the current management flux and near-term strategic uncertainty" at the company for dropping their view on the bank's financial outlook from stable to negative – a clear indication that a rating downgrade could be on the cards.
The chairman, Marcus Agius, resigned on Sunday night, but is now in charge of finding a replacement for the chief executive, Bob Diamond, who quit on Monday, closely followed by the chief operating officer, Jerry del Missier.
The exodus followed the £290m of fines imposed by regulators on both sides of the Atlantic over the Libor-fixing affair last week.
"Shareholder and political pressures on Barclays, which resulted in the resignation of the bank's CEO, COO (previously the head of the investment bank) and the stated intention of the chairman to resign, could lead to broader pressure on the bank to shift its business model away from investment banking and reform perceived failures in its business culture," Moody's said.
The agency believes that the bank "could be challenged to replace the three senior staff and in particular find a new CEO". But Moody's made it clear that it was the "disruptive management changes" rather than the Libor investigations which could hit the bank's rating.
Barclays' current rating is just two grades above junk status.
Moody's said that it was likely to experience further downward pressure "if the bank proved unable to restore a stable management structure over the coming months; or if there are indications that the current developments were to have a financial impact sufficiently large to put pressure on capital ratios and/or negative implications for the bank's business model".
The ratings agency also highlighted the difficulty of finding a new chief executive who would be credible enough to repair Barclays' image but also have enough knowledge of investment banking, which is such a large part of the business. S&P agreed, praising Mr Diamond's skill at steering the bank through the financial crisis.
Barclays is still running a beauty parade to appoint headhunters to find Mr Diamond's replacement. In the meantime, Bill Winters, the former co-chief of JP Morgan's investment bank, has overtaken Barclays' head of retail banking, Antony Jenkins, as the bookies' favourite.