A 19% decline in Accenture's shares erased nearly $18 billion in market value, helping Tata Consultancy Services (TCS) overtake the US-based IT services firm in market capitalisation for the first time since 2021. TCS was valued at about $84.6 billion at Thursday's close, compared with Accenture's $77.6 billion. Accenture's stock fell after it trimmed its full-year growth outlook.