Pakistan, July 18 -- On any weekend in Pakistan, the restaurants are full. Wedding halls sparkle late into the night. Shopping malls remain crowded. Roads are packed with SUVs, and social media feeds overflow with vacations, new gadgets and carefully curated lifestyles.

If appearances were our only measure, we would conclude that Pakistan's middle class is thriving.

It is not. The country's newest poor no longer stand in ration queues or wear torn clothes. They wear office suits, carry smartphones, drive financed cars and send their children to private schools. They celebrate birthdays in cafes, attend destination weddings and upload smiling family photographs online. Yet behind those images lies a financial reality that is becoming inc...