 JPMorgan's credit card arm, the biggest in the country, said charge-offs on loans rose by nearly two-thirds from a year earlier. The rise in part reflected a normalization from years of historically low levels, Chief Financial Officer Jeremy Barnum told reporters, but lower-income consumers have started to shift spending to non-discretionary from discretionary purchases, which is historically a sign of weakness, he said. Meanwhile, Citi Finance Chief Mark Mason said,