Citigroup Inc C shares are trading lower by 1.9% to $44.98 Tuesday afternoon. Shares of banking and financial services stocks at large are trading lower after Moody's cut the credit ratings of 10 banks and placed others under review for potential downgrades. If regional banks' credit rating downgrades are due to broader economic or industry-specific challenges, it could lead investors to question whether Citigroup might also face similar challenges. This perception of systemic risk within the financial sector could lead to a decrease in investor confidence in Citigroup's stability. Citigroup's revenues and profits could be influenced by the financial health of its regional banking counterparts. If these banks face credit quality deterioration or other financial issues, it might impact Citigroup's loan portfolios, investment portfolios, or other aspects of its business, potentially leading to a fall in its stock price.