New York Attorney General Andrew Cuomo said he reached a settlement worth more than $7 billion with Citigroup that requires the company to buy back auction-rate securities from about 40,000 customers around the country. Cuomo had threatened to charge the biggest U.S. bank with fraudulent sales of auction-rate securities and with the destruction of key documents. The settlement announced Thursday requires Citigroup to buy back securities from retail customers, charities, and small-to-mid-sized businesses by November. Citigroup also must pay New York state a $50 million civil penalty.