Citi Fat-Finger Errors, Aging Software Drive Tech Boss’s Agenda

Just before Citigroup Inc.’s tech chief faced his first global town hall meeting, he got some pointed advice from his teenager: Make sure the technology works.

That hasn’t always been a given at Citigroup.

For the past year, Tim Ryan — an earnest, soft-spoken Bostonian who was once told in high school he’d never amount to much — has been untangling legacy software and data systems that have irked the bank’s moneymakers and regulators, and have at times made it an industry punchline. The most notorious moments: “fat-finger” errors that accidentally credited fortunes to recipients.

Now, his division ...