** Watches of Switzerland WOSG.L gains as much as 11% to 354p; top pct gainer on FTSE mid-cap index .FTMC
** Luxury watch retailer anticipates no material impact from U.S. tariffs in H1 2026
** Expects to report H1 results in line with its estimate
** Says, "The stability we saw in UK luxury watch and jewellery markets during the second half of FY25 has continued"
** As of last close, WOSG falls 43% this year
(Reporting by DhanushVignesh Babu in Bengaluru)
((DhanushVignesh.Babu@thomsonreuters.com;))