* To buy back up to 7% of its own shares
* Buyback to begin on Monday, will take place over a year
* SoftBank shares fall as much as 9.6%, end down 5% (Adds statement from Elliott)
By Makiko Yamazaki and Tim Kelly
TOKYO, March 13 (Reuters) - SoftBank Group Corp is buying back up to $4.8 billion of its shares after their recent slump, a move that partially met the demand of activist fund Elliott Management but failed to soothe investors panicking from the coronavirus pandemic.
The Paul Singer-led hedge fund backed SoftBank's buyback of up to 7% of its shares for as much as 500 billion yen ($4.8 billion).
It comes after Elliott pressed SoftBank earlier this year for $20 billion in stock buybacks by selling down its stake in Chinese e-commerce giant Alibaba, and follows a nearly 25% decline in the Japanese investment group's shares in March.
"SoftBank's announcement of its intention to commence an initial buyback program of 500 billion yen is clearly an important first step in addressing the company's significant undervaluation, and one that Elliott supports," Elliott said in a short statement on Friday.
The activist investor, which manages roughly $40 billion in assets, said SoftBank would be able to pursue more buybacks following the completion of the merger between its unit Sprint and T-Mobile.
A SoftBank spokeswoman said the company decided to go for the buyback after considering the risk that stock market volatility could increase the deep discount that SoftBank's stock has relative to the value of its holdings.
No fresh financing is planned for the buyback, the spokeswoman said.
"With SoftBank shares trading more than 50% below fair value, buying back shares is a good idea. Not only is it a good price but previous buybacks have helped that holding company discount to meaningfully narrow," said Kirk Boodry, an analyst at Redex Holdings, who publishes on the Smartkarma platform.
SoftBank shares fell as much 9.6% to a 14-month low on Friday amid a crash in global stock markets, but pared losses to close down 5% in Tokyo.
The buyback will begin on Monday and will take place over a year, the company said in a statement.
SoftBank said last month it plans to borrow up to 500 billion yen from 16 domestic and foreign financial institutions using part of its stake in telecoms firm SoftBank Corp as collateral to boost its cash on hand.
The loan comes as its finances have been squeezed by losses at its $100 billion Vision Fund and as SoftBank injects its own cash into a successor fund due to lackluster appetite from outside investors.
Elliott, one of the world's most powerful activist investors, has amassed a holding of almost $3 billion in SoftBank and has pressured the Japanese firm on a range of issues including buybacks and improving transparency.
SoftBank founder and CEO Masayoshi Son, who has repeatedly claimed that SoftBank shares are chronically undervalued, said last month that while open to potentially buying back shares he is no hurry to sell down the Alibaba stake.
The buyback plan unveiled on Friday follows a 600 billion yen share repurchase, its largest ever, announced a year ago. It funded that program with proceeds from the bumper IPO of SoftBank Corp.
$1 = 104.8000 yen Reporting by Tim Kelly, Makiko Yamazaki and David Dolan; Additional reporting by Bharath Manjesh; Writing by Miyoung Kim; Editing by Edwina Gibbs, Muralikumar Anantharaman and Arun Koyyur