Hedge fund Marshall Wace has taken a £155.6 million short position against NatWest Group, the bank formerly known as  RBS.

Bloomberg reported that the bet is the largest-ever disclosed short position against NatWest since records began in 2012.

Latest disclosures to the UK’s Financial Conduct Authority show the hedge fund increased its bet against NatWest on March 23, increasing its position from 0.51% as of March 10, representing about 0.61% of the bank.

The UK taxpayer remains NatWest’s biggest shareholder — with a 42% stake — about 15 years after the UK government rescued what was then called Royal Bank of Scotland in a £45.5 billion bailout.

On April 3, UK Government Investments Ltd (UKGI) said it was extending a trading plan to help sell down the taxpayer’s stake in NatWest Group by another two years as it reduces the UK state’s remaining ownership of the bank.

A gradual series of share sales returned the bank, bailed out during the 2007-09 global financial crisis, to majority private ownership last year.

The UK government said the stake sale plan will continue to be managed by Morgan Stanley & Co. International plc and that Goldman Sachs International is acting as Privatisation Adviser to UKGI.