Top Dutch bank ING announced Tuesday it was selling 45 million ordinary shares in NN Group, thereby relinquishing its majority stake in the giant insurer.

"Following a successful completion of the transaction, ING's stake in NN Group's outstanding capital is expected to decrease to approximately 42.4 percent from a current 54.8 percent," ING said in a statement.

"ING has previously announced that it intends to divest its remaining stake in NN Group over time," the Amsterdam-based bank added.

NN Group will buy back shares worth 150 million euros ($163 million) as part of the deal, ING said.

NN Group listed on the Amsterdam stock exchange last year in one of Europe's biggest initial public offerings for 2014.

Leading bank ING is selling its NN Group stake as part of the final stages of restructuring, after paying back a massive debt following a 10 billion euro government bailout during the 2008 banking crisis.

The sell-off is expected to be completed by the end of 2016.

Earlier restructuring led ING to sell its insurance businesses in Canada, Australia, New Zealand, Latin America and Asia as it sought to pay back the loan as well as an additional three billion euros in interest.

It paid the final amount in November last year, some six months ahead of schedule, and in February it announced its first dividend payment since being bailed out in 2008.

NN Group is a leading Dutch insurer and investment management company that has branches in more than 18 countries, mainly in Europe and Japan.

It posted pre-tax earnings of 905 million euros in 2013.