Analysts, investors and some BNP Paribas officials are growing increasingly concerned about the possible financial ramifications of penalties the French bank is facing for allegedly violating US sanctions.

Shares in the bank ended down 2.4% in Paris, the second-biggest loser in the CAC-40 index, a day after The Wall Street Journal reported that US authorities are pushing for BNP to pay more than $10 billion to resolve the investigation, which would be one of the largest penalties the country has ever levied on a single bank. The cost of insuring BNP's debt against possible default rose, while its bond prices fell.