Ad group S4 Capital climbs on potential merger with MSQ partners
** Shares of Martin Sorrell's ad group S4 Capital SFOR.L up 12.9% at 23.95 pence ** Co confirms it is in preliminary talks for a potential merger with MSQ Partners, a marketing services firm majority owned by One Equity Partners ** Co says any potential transaction would involve acquisition of MSQ Partners by S4 ** Including session moves, SFOR stock down ~27% YTD (Reporting by Nithyashree R B in Bengaluru) ((NithyashreeRB@thomsonreuters.com))