Advanced Micro Devices Inc. AMD, +4.01% announced plans Tuesday to raise more than $1 billion through an offering of stock and debt, and shares declined in response. The chipmaker has been trading at its highest prices in nearly 5 years of late, after announcing a new line of semiconductors dubbed Zen. Tuesday afternoon, AMD said it would seek to sell $600 million in fresh shares and $450 million in convertible senior notes, with another $157.5 million in shares and debt available to underwriters if demand exists. AMD plans to use the new funds to pay off debt or outstanding senior notes, with any remaining capital going to other corporate purposes such as capital expenditures. AMD stock, which has moved as high as $8 in the recent run-up, fell lower than $7 in late trading thanks to an after-hours decline of 5%.