Mumbai-based Reliance has approached some investors from that deal to take stakes in the retail business, although "it is understood not all will participate", one of the sources told Reuters, asking not to be named as talks are private.
The sources did not specifically name which companies Reliance had approached.
"It is a strategic relationship that these funds have with Reliance which goes beyond one deal," said this source.
PIF and Mubadala declined to comment.
Reliance Retail, which has nearly 12,000 stores and sells everything from groceries to iPhones, acquired rival Future Group's retail arm last month.
This week, it announced a $1 billion (roughly Rs. 7,341 crores) investment from US private equity firm Silver Lake.
"We've received strong interest from strategic and financial investors in Reliance Retail," Ambani told shareholders at the company's annual meeting in July.
Bloomberg News cited on Thursday an unidentified person with knowledge of the matter as saying Reliance was offering to sell a roughly 40 percent stake in its retail arm, worth about $20 billion (roughly Rs. 147020 crores), to Amazon.
Amazon has held talks about investing in Reliance Retail and expressed an interest in negotiating potential deals, but has made no decision, Bloomberg's report said.
Reuters could not independently verify whether Amazon and Reliance were in fresh discussions.
Last year, Reuters reported that Amazon had been mulling a proposal to purchase an up to a 26 percent stake in Reliance Retail. Earlier this year, the Economic Times reported that Amazon was in talks to buy a 9.9 percent stake in Reliance Retail.
Amazon did not respond to a Reuters request for comment.
Reliance said it did not comment on speculation and rumours, adding it "evaluates various opportunities on an ongoing basis."
Shares in Reliance rose as much as 8.5 percent on Thursday, making it the first listed Indian firm to achieve a market capitalization of more than $200 billion (roughly Rs. 1,469,950 crores).
Ambani, the world's fifth richest man, is shifting his empire's focus towards retail after successfully building India's largest telecom network by customers in four years, hoping to take a dominant position as India's huge consumer market comes of age.
For Reliance, a deal with Amazon could potentially leverage the e-commerce giant's global experience in technology, supply chain and logistics, as it aims to connect mom-and-pop stores across India digitally through its Jio telecoms network.
For Amazon, a stake in Reliance Retail could give it access to the Jio telecoms platform and its vast retail footprint across India. It could also add more firepower to Amazon's local lobbying efforts, as the Ambani family is well-connected.
The reported discussions come at a time when Amazon has been facing tighter regulatory scrutiny and anti-trust cases in India, with brick-and-mortar retailers alleging it uses unfair business practices to operate its online marketplace in the country, an allegation Amazon denies.