SoftBank Corp Chief Executive Masayoshi Son on Wednesday declined to comment on reports that his companys subsidiary Sprint Corp is looking to buy U.S. rival T-Mobile US. Son also declined comment on U.S. regulators reported skepticism about the potential merger between Sprint and T-Mobile. Speaking at a news conference to brief on SoftBanks financial results, Son, who is also chairman of Sprint, said he could not comment on rumors in the industry. (Reporting by Sophie Knight;