SINGAPORE June 4 -- Shanghai zinc prices fell by their 5 percent limit on Friday, touching their downside threshold for the second time this week, under pressure from high stockpiles and fears of slowing demand growth.

Benchmark third-month Shanghai zinc SZNc3 fell 760 yuan from Thursday's settlement to 14,350 yuan, on track for a loss of around 10 percent this week, its biggest weekly fall since the end of January.

Investors fear rising stocks of metal in Shanghai warehouses, up 75 percent this year to a record 300,000 tonnes, and that Beijing's measures to cool the economy will take hold in the second half, hitting demand.