A mystery trader nicknamed the 'Dude' is causing chaos in Turkey's financial markets

A mysterious trader nicknamed "the dude" is causing chaos in Turkey's financial markets, making huge bets, scaring away competitors, and moving the markets massively.

Bloomberg reports that the trader - who shares their nickname with a character from cult 1990s comedy The Big Lebowski - first appeared in 2014, betting $450 million (£314.6 million) in a single day.

"Nobody knows anything for sure," Turgay Ozaner, a partner at Istanbul Portfolio, told Bloomberg. "And this is Turkey, where usually we all know what's going on" he added.

The "dude" is proving very hard to track down as they are jumping from brokerage to brokerage on a frequent basis. Currently the trader is using the Yatirim Finansman brokerage. In 2014, the firm carried out around 2% of trades undertaken on the Istanbul stock exchange, but now does more than half of all trading on the exchange some days.

By the end of February, Yatirim Finansman had bought assets in excess of 1.2 billion turkish lira (£293.64; $420 million), compared to its nearest competitor, UBS, which has bought just over 700 million lira's (£170 million; $243 million) worth, according to data from Bloomberg.

The mysterious "dude's" trades have also helped increase the average daily volume of trading on Turkey's blue-chip Borsa Istanbul by 8% this year.

The unknown trader is making such big bets that at least one unnamed bank has stopped shorting Turkish stocks as it believes that the trader is using an automated, algorithmic trading system to make their trades.

One fund manager, Kerem Baykal said that the trader has "deeper pockets than anyone else in the game and can move the market in any direction."

Neither Borsa Istanbul, nor Yatirim Finansman had made any comment on the mysterious trader at the time of writing.