TOKYO (Reuters) -SoftBank Group Corp’s shares jumped as much as 7% on Wednesday after Bloomberg News reported that the group was considering buying back shares to boost CEO Masayoshi Son’s stake so he could squeeze out remaining investors. SoftBank’s shares are seen as chronically undervalued by company executives, with debate around the benefits of a buyout intensifying as they plunged to lows in March. Record share buybacks and a string of asset sales have driven a 180% share price gain to two-decade highs since then, giving the group a market capitalization of around $140 billion and raising the hurdle for a buyout. Management buyouts remain rare in Japan, where being listed is a mark of status for companies, and any move to take SoftBank private faces considerable internal opposition. Son owns a quarter of SoftBank’s shares and would need to lift his shareholding ratio to two thirds to squeeze out minority shareholders. SoftBank’s revised scheme would aim to buy back shares when the price dips rather than launching a formal buyout with the aim of limiting the premium paid, Bloomberg reported citing unidentified sources. The group spent $1.6 billion on buybacks in November, an increase from the previous month but less than half its July outlay. SoftBank was not immediately reachable for comment. The group has raised $80 billion through asset sales causing speculation about how Son, who is said to prefer buying over selling, will deploy the cash pile. “SoftBank has grown to what it is through an enthusiastic use of other people’s money which would end with privatization,” said Kirk Boodry, analyst at Redex Research, adding a buyout would limit Son’s freedom to invest elsewhere.