Low-income consumers are still struggling. Now the cracks are starting to show for higher-income ones, survey finds.

Mizuho said Monday its August consumer survey found low-income consumers, those who earn less than $50K a year and account for 22% of total U.S. household spending, continued to struggle. The cracks were also starting to show for consumers in higher brackets. The middle-income cohort, for example, or people who earn $50K to $100K a year...