Signet is reducing shares outstanding by 15% in a special transaction.Shares of Signet Jewelers (SIG -4.07%), the world's largest diamond jewelry retailer, were soaring on Wednesday after the company delighted investors with a share buyback and raised its guidance to adjust for the diminished share count.As a result of the buyback, the company is raising its adjusted earnings-per-share guidance from $9.08-$10.48 to $9.90-$11.52, and it will provide an additional boost to fiscal 2026 earnings as it benefits ...