** Shares of British banknote maker De La Rue jump 21.3% to 114 pence, its highest since Feb 2022

** Stock top gainer on the FTSE small cap index

** Co to sell its authentication business for 300 mln pounds ($391 mln), incl debt, to Crane NXT

** Says sale allows it to focus on banknote printing, reduce debt, address pension deficit

** As of last close, stock had risen about 9% YTD

($1 = 0.7663 pounds)

(Reporting by DhanushVignesh Babu in Bengaluru)

((DhanushVignesh.Babu@thomsonreuters.com;))