Singh will join ByteDance India, a technology company specialising in content platforms as its VP, Monetisation
Kyoko Matsushita takes on new role.
Ex-WPP boss' fledging venture grew by more than a third in first quarter of 2019.
S4 Capital, the advertising business Sir Martin Sorrell launched after leaving WPP last year, has published its first annual report.
Read was handed a special £1.5m bonus as COO last year, with first of three payments due next week.
Former chief executive would have got an estimated £5m more if WPP's share price had not dropped.
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