LONDON — HSBC avoided a legal battle that could further savage its reputation and undermine confidence in the global banking system by agreeing Tuesday to pay $1.9 billion to settle a US money-laundering probe. Europe's largest bank by market value will pay the biggest penalty ever imposed on a bank after facing accusations it transferred funds through the US from Mexican drug cartels and on behalf of nations such as Iran that are under international sanctions. “We accept responsibility for our past mistakes,” said HSBC Chief Executive Stuart Gulliver. “We have said we are profoundly sorry for them, and we do so again.” It's the latest scandal to hit banks since the financial crisis started in 2008. Hours earlier, Standard Chartered PLC, another British bank, signed an agreement with New York regulators to settle a money laundering investigation involving Iran with a $340 million payment. “These banks are operating in an environment where you can't afford to have uncertainty attached to your name, and they are dependent on confidence from their investors,” said Sabine Bauer, director of financial institutions at Fitch Ratings. “And that makes them keen to get past such events very quickly and settle.” — AP