By Aditya Kalra and Kane Wu

NEW DELHI/HONG KONG (Reuters) - Indian billionaire Mukesh Ambani targets a 2025 Mumbai listing for his telecom business Jio, valued by analysts at over $100 billion, and plans to launch his retail unit's IPO much later, two people familiar with the matter told Reuters.

Reliance Industries' boss Ambani hasn't updated his IPO timelines after saying in 2019 that Reliance Jio and Reliance Retail would "move towards" a listing within five years.

In recent years, Ambani, Asia's richest man, raised $25 billion collectively for digital, telecom and retail businesses from the likes of KKR, General Atlantic and Abu Dhabi Investment Authority, valuing both ventures at above $100 billion.

The two sources said Reliance has now firmed up plans to launch the Reliance Jio IPO in 2025 as it internally believes it has achieved a stable business and revenue stream in becoming India's No. 1 telecom player with 479 million subscribers.

But the retail business IPO is not expected until after 2025 as the company first needs to address some internal business and operational challenges, said the first source.

Oil-to-retail conglomerate Reliance Industries did not respond to a request for comment.

Reliance Jio is set to lock horns with Elon Musk if he launches his Starlink internet service in India, and Jio, which is also backed by Google and Meta, has partnered with Nvidia to develop AI infrastructure.

The sources said there was no internal decision yet on a valuation of Reliance Jio and bankers haven't yet been appointed, but Jefferies in July pegged the company's estimated IPO valuation at $112 billion.

Reliance, however, aims for the 2025 Jio IPO to be India's biggest ever, overtaking Hyundai India's record $3.3 billion IPO this year, said the first source.

Both the sources, who declined to be named as the discussions are private, said the IPO timelines can still change.

Indian markets recently scaled record highs and by October, 270 companies had raised $12.58 billion from Indian IPOs this year, eclipsing the $7.42 billion raised in all of 2023.

RETAIL FIXES NEEDED

Reliance's current thinking is to not list the retail unit in the same year as JIO, as it doesn't want to hit the market with two big IPOs around the same time, said both the sources.

More critically, the first source said, there are "operational issues" Reliance internally wants to fix at the retail unit, which runs India's biggest grocery store network of 3,000 supermarkets, before going for an IPO.