Hong Kong and mainland stocks had their biggest rally in nearly eight months yesterday after the European Central Bank announced it would buy bonds to ease borrowing costs and Beijing approved substantial infrastructure investments.

Companies in the materials and industrial sectors had the biggest gains on optimism the measures would boost sluggish global economic conditions.

The benchmark Hang Seng Index closed up 3.09 per cent, or 592.86 points 19,802.16, marking its biggest single-day gain since January 17 this year.