Don’t worry Sweden, your stock market crash wasn’t due to any of your domestic economics… Instead, it was done at the hands of a Citi Group trader after he made an erroneous trade at his London trading desk. Not too big of a deal? What if we told you it led to a $315 Billion USD sell-off?

The bank cleard everything up in an emailed statement this week:

“This morning one of our traders made an error when inputting a transaction. Within minutes, we identified the error and corrected it.”

For those unaware, an erroneous trade is a stock transaction that “deviates so much from the current market price that it is considered an error.”

All markets are interconnected in the modern-day economy and erroneous trades usually have a severe impact on global markets. Indexes in Denmark, Norway, Germany, Italy, and France also sank due to the trade. This also isn’t the first occurrence. On May 6th, 2010, the Dow lost 9% of value in a time frame of 36 minutes after an erroneous trade caused the famous “flash crash.”

After the May 6th crash, investment regulators began to implement measures that would help future investors. Equity markets still continue to be sensitive to erroneous trades which raises the question of the effectiveness of the previously implemented measure and if regulators are even doing enough to protect the everyday investor.

The first line of defense against flash crashes would be a well-thought-out diversified portfolio of risk and risk-off assets. For those of you trading with excessive amounts of leverage, liquidation at mass amounts could occur in a matter of seconds.

The Australian Central Bank made a decision to raise the official crash rate by 25BPS to 0.35% hours before Citi Group announced the news. The Fed is also anticipating making a similar decision on Thursday.