Doosan Group said Monday the firm sold its iconic building Doosan Tower to real estate investment company Mastern Investment Management for 800 billion won ($689 million).

Doosan said the sale is aimed at improving the group’s financial structure.

The group sold Doosan Solus and Doosan Tower one after another to normalize the management of its struggling construction firm Doosan Heavy Industries & Construction. It is also seeking to sell other subsidiaries such as Doosan Infracore.

As Doosan faced financial difficulties earlier this year, it attempted to restructure its workforce, but eventually received a total of 3.6 trillion won from creditors.

Doosan Tower, located in Dongdaemun Fashion Market in Seoul, was completed in 1998. It has a total floor area of 122,630 square meters with seven basement floors and 34 ground floors.

By Shin Ji-hye (shinjh@heraldcorp.com)