Citigroup, which has been fighting creditors of Revlon after inadvertently sending them $900 million, says that the transfer was due to human error, according to  Bloomberg. The financial institution accidentally sent the money earlier this month, just one day after Revlon's creditors had sued the cosmetics firm over its restructuring practices. Citi said shortly afterward that the transfer had been made in error, and it asked them to return the money. While some did so, others have refused, saying that Revlon was deeply in debt and they consider the transfer, accidental or no, as payment toward that debt. The bank has now needed to file several lawsuits to try and recover the money as investment groups fight tooth and nail to keep it.

According to Bloomberg, Citigroup had been acting as an agent for Revlon’s loans, collecting funds from the company and distributing them to creditors. The bank meant to make interest payments on Revlon’s behalf, but the sum it sent was more than 100 times bigger than intended. The bank said that the accidental transfer was caused by a single person who didn’t manually select the correct system options in its loan operation software, resulting in the far larger transfer. The identity of this employee is currently unknown.

In that person's defense, though, this is far from the most expensive blunder made by an individual outside a head of state. For instance, a keyboard typo, known colloquially as a "fat finger error," caused an oil company to lose $3 billion in market value after mistakenly opening a 15.2 million-share closing auction. This was a paltry loss, though, compared to a typo that caused electronics giant Samsung to distribute $108 billion worth of stock that did not exist. While the stocks weren't technically real, 16 employees sold them anyway, which in turn, led those who had actual stock to sell their shares too. Samsung's stock value lost 12 percent in the span of mere minutes.

And even if this employee's error was as big, or bigger, than some others, the employee might point out that the mistake is not as bad as the one made by Stephen Perkins, a former crude oil trader. In 2009, he got blackout drunk in the wee morning hours and traded about $500 million worth of oil futures, roughly 69 percent of the total volume of oil being traded and 10 times the average trade volume. The move caused the price of oil the next day to spike and then crash, ultimately halting trading as everyone wondered what in the world was going on. After a judge barred him from working as a trader for five years and forced him into a rehab program, he said that "Mr. Perkins poses an extreme risk to the market when drunk."