Twenty-First Century Fox said Tuesday it’s withdrawing its offer to acquire Time Warner, abandoning plans to create one of the world's largest media conglomerates. Chairman and CEO Rupert Murdoch said in a company statement that the proposal had "significant strategic merit," and its approach had "always been friendly." But he said Time Warner's refusal to accept an $80 billion offer, coupled with other factors, led to his decision to withdraw the proposal. "The reaction in our share price since our proposal was made undervalues our stock and makes the transaction unattractive to Fox shareholders," he said. "These factors, coupled with our commitment to be both disciplined in our approach to the combination and focused on delivering value for the Fox shareholders, has led us to withdraw our offer." Fox also announced that its board had authorized a $6 billion share repurchase program. Time Warner stock dropped more than 12 percent in after-market trading on the announcement. Fox shares jumped almost 8 percent. Time Warner said it is "committed to enhancing long-term value and we look forward to continuing to deliver substantial and sustainable returns for all stockholders."