Broadcom Ltd. AVGO, -0.37% shares rose in the extended session Thursday after the chipmaker announced a large share buyback plan that had been anticipated after its deal to acquire Qualcomm Inc. QCOM, +0.35% fell apart. Broadcom shares rallied 4.5% after hours, following a 0.4% decline to close at $239.43 Thursday. Broadcom said its board authorized the repurchase of up to $12 billion in shares out to Nov. 3, 2019. "We are maintaining our policy of delivering 50% of trailing 12-month free cash flow to shareholders in the form of dividends while adding the ability to use the balance of our free cash flow not only for acquisitions but also for opportunistic buybacks," said Tom Krause, Broadcom's chief financial officer, in a statement. In mid-March, Broadcom withdrew its offer to buy Qualcomm after the deal was blocked by President Donald Trump, and analysts said the company would likely pursue share buybacks.