Zain Iraq, the country's biggest mobile phone operator by subscribers, has received approval from the stock market regulator to list on Baghdad's bourse, parent firm Zain said on Thursday.

Iraq's three mobile network firms were required to float a quarter of their shares and join the Iraq Stock Exchange (ISX) by August 2011 as part of their 15-year licences awarded in 2007.

So far only Ooredoo unit Asiacell has floated, joining the ISX in February 2013. Daily fines for not doing so are being levied against the other operators: Zain Iraq and Korek, the smallest of the three.

Zain said in April its Iraqi unit had applied to list in Baghdad. This has now been approved by the Iraq Securities Commission (ISC), the company said in an emailed statement.

“The company is in the process of carrying all necessary and statutory procedures and steps to ensure this is completed in a timely fashion,” Zain's statement said, adding it would reveal the mechanics of its flotation “over the next few weeks”.

In April, a source told Reuters that Zain Iraq would not follow the book-building process Asiacell used.

Zain Iraq must list within two months of receiving bourse regulator approval otherwise its application will be void.

Iraq did not have a mobile phone market under Saddam Hussein but boomed following his fall in 2003 to become the country's second-largest sector after oil.

But stiffening competition and network shutdowns in areas controlled by Islamic State has led to profit declines at Zain Iraq and Asiacell. Korek does not publish its results.  - Reuters