Mukesh faces data snag as.

There's a wrinkle in plans made by Asia's richest man to take on Amazon.com Inc and Walmart Inc on his home turf in India: his telecom and retail businesses can't share data. Billionaire Mukesh Ambani, chairman of Reliance Industries Ltd., has outlined how he will marry the might of his group's 9,900-plus retail stores and 280-million strong telecom user base to bolster his e-commerce venture. A senior Reliance executive says that any data sharing on customers between the two, could run into a legal wall. "They are different companies so there are data privacy rules," Ashwin Khasgiwala, Reliance Retail Ltd.'s chief financial officer said at a conference in Mumbai on Tuesday. "They're different platforms," he said while declining to elaborate on how the group plans to overcome it.

While its brick-and-mortar retail businesses are housed in Reliance Retail...