IT’S OFFICIAL. The world’s biggest e-commerce deal has been signed. American retail giant Walmart Inc will pay US$16 billion for a 77 per cent stake in India’s largest start-up Flipkart.

NEW DELHI - With 100 million new internet users every year, Amazon is betting big on India, but a major new investment in homegrown rival Flipkart means the battle to dominate the fast-growing e-commerce market is set to heat up.