The company Nasdaq, which operates the Stockholm Stock Exchange, initially had no explanation.

A few hours later, it could be stated that it was neither a cyber attack nor an internal IT error.

It was simply a player that sold a very large amount of shares, something that had effects in a flash.

According to SVT's Peter Rawet, the stock market today is more anxious and nervous than in a long time, which means that it is extra sensitive to changes.

- It is ultimately about trust in the stock market, says Peter Rawet.

- We have an elephant in the financial porcelain shop, that the actions of a single player risk that very many can lose money.

What really happened on Monday morning?

SVT's Peter Rawet explains in the video above.