Consumer spending slowed and household finances weakened across all income levels last month. But households earning $100,000 a year or more reported shaving more off their spending than less well-off households did, according to a report released this week by Morning Consult, a decision intelligence company. The report also found that real monthly spending among U.S. adults fell by 4.3% from November to December. Even so, 21.3% of U.S. adults said their monthly expenses exceeded their monthly income in December, up from 19.2% in November. On average, households earning $100,000 a year or more said they spent about 10% less...