Reliance Industries, controlled by Asia's richest man Mukesh Ambani, is lining up investors in its retail unit after the conglomerate raised just over $20 billion this year from global investors, including Facebook Inc, by selling stakes in its Jio Platforms digital business.

The Mumbai-headquartered Reliance has approached investors in Jio Platforms about buying stakes in its retail arm, Reuters had reported. While Silver Lake, another one of Jio Platforms' backers, said earlier this month it will invest $1.02 billion in Reliance Retail.

KKR's investment for a 1.28% stake in Reliance Retail values the company at 4.21 trillion rupees ($57 billion), Reliance said in a statement.

"Retail, whether online or offline, is a very capital-intensive business, so for Reliance making sure that their retail venture has a funding pipeline of its own is important," said Devangshu Dutta, the chief executive of retail consultancy Third Eyesight.

KKR, which announced its biggest investment in Asia with a $1.5 billion stake buy in Jio Platforms in May, said it was deepening its relationship with Reliance.

Reliance Retail is "empowering merchants of all sizes and fundamentally changing the retail experience for Indian consumers," KKR co-founder Henry Kravis said in the statement.

Reliance, already India's biggest retailer with roughly 12,000 stores, forged a $3.38 billion deal last month to acquire rival Future Group's retail business.

The Indian conglomerate is also attempting to expand its so-called new commerce venture, which ties neighborhood stores to Reliance for online deliveries of groceries, apparel and electronics in a space currently dominated by Walmart Inc's Flipkart and Amazon.com Inc's Indian arm.

"Anyone taking on the deep-pocketed Amazon and Walmart has to make sure they are equally well-capitalized," Dutta said.

($1 = 73.5700 Indian rupees)

(Reporting Sankalp Phartiyal; Additional reprting by Philip George and Chandini Monnappa in Bengaluru; Editing by Shounak Dasgupta and Sherry Jacob-Phillips)

By Sankalp Phartiyal