This could provide some pop for News Corp shares, which have declined more than 12% over the last five days as the News Of The World phone-hacking scandal mushroomed. The company says this morning that its board of directors has authorized a $5 billion stock repurchase over the next 12 months, up from $1.8 billion it had previously approved. The buyback applies to the company’s Class A shares, the ones that ordinary investors typically own, as well as the Class B ones that Rupert Murdoch and his family control. News Corp says that the purchases will begin after August 15. It also warns that while the board has authorized the transactions, the company isn’t required to repurchase any stock and the program “may be extended, modified, suspended or discontinued at any time.” But Wall Street will closely watch what the company does: In a report this morning Nomura Equity Research analyst Michael Nathanson says that “pressure is growing for News Corp to address equity returns to shareholders.”