。
She covers the financial markets.
Literal
She [topic-は] financial-market [genitive-の] coverage [object-を] is-in-charge-of.
取材 (literally 'taking material') is the journalist's word for newsgathering — covering a beat, conducting interviews, gathering source material. 担当する ('to be in charge of') is the workplace verb for assigned responsibility — every Japanese workplace has its 担当者 (the person in charge of X). The combination 取材を担当する is the standard way to say 'cover a beat' in journalism. 金融市場 is the neat compound 'finance + market' for 'financial market.'