ING priced shares at the mid-range price of 20 euros ($27.3) a piece on Tuesday, valuing NN Group at 7 billion euros ($9.56 billion). The Dutch bank sold 77 million shares in NN Group. The company's shares are now trading at 21.08 euros.
Proceeds from the initial public offering are expected to be around 1.5 billion euros, ING said, while reducing the company's stake in the insurance group to 71.4 percent.
ING was bailed out by European Union regulators in 2008 in a 10 billion euro deal. As part of the package, the Dutch firm was forced to spin off its insurance arm. ING will reduce its stake to 50 percent by the end of 2015 and divest the remainder of the business by the end of 2016.
The CEO of NN Group said the group is pressing forward with new opportunities as the timetable provides ING with a "clear framework" to exit the business.
"Outside of the Netherlands we will expand the operating leverage that is embedded in our wealth position and growth businesses especially in central and eastern Europe and in Japan," Lard Friese, chairman and CEO of NN Group, told CNBC in a TV interview.
"In Europe there is an underpenetration of life insurance and pensions and we believe as the macroeconomic backdrop in Europe will gradually improve, that underpenetration will translate into new growth opportunity which we are very well placed to capture."
As part of the restructuring plan, ING is also looking to divest the U.S. insurance business Voya Financial by the end of 2016.
- By CNBC's Arjun Kharpal