Here’s a play-by-play of how Citi sent Revlon creditors $900 million by mistake

• In August, Citibank mistakenly sent $900 million to Revlon lenders.
• On Tuesday, a Manhattan judge ruled that asset managers for the lenders can keep the money.
• Here’s how a failure in Citibank’s review process led to one of the biggest blunders on Wall Street.

It was around 9 a.m. on Aug. 12 when Arokia Raj first realized that something had gone terribly wrong.

Raj, a member of a Citigroup team that processes and services asset-based loans, was reviewing the previous day’s transactions when he noticed large gaps in the numbers – a discrepancy just under $900 million.

Raj quickly put two and two together: The figure matched, down to the decimal point, the outstanding principal balance on a loan that the beauty company Revlon had taken out nearly five years ago.