The Globe and Mail reports in its Friday edition that for a year, Wall Street's dominant theme has been the so-called K-shaped economy, in which the well-to-do have powered financial activity despite lower earners' struggles. A Reuters dispatch to The Globe says this week, the country's big banks reported a broadly disappointing set of quarterly earnings, marking the first stumble after a year-long spree of rising markets and softening regulations paid off handsomely for the finance set. Results at Bank of America, Citigroup, JPMorgan and Wells Fargo all fell short of expectations and their shares fell. Troubles ranged from delayed merger deals (JPMorgan) to stubborn expenses (Citi) to questions about the efficacy of artificial-intelligence tools (Bank of America). Banks that do business largely with rich individuals and corporations, such as Goldman Sachs and Morgan Stanley, fared comparatively better. Results from major lenders are watched because they contain hints about the state of the economy and American consumers. Now the banks are facing President Donald Trump's threatened 10-per-cent cap on credit card interest rates. Bankers argued that charging lower rates would cause them to lend less to riskier borrowers.