Global stock markets looked set to build on this week's rally on Wednesday, with Japanese, South Korean and Hong Kong indexes posting strong gains overnight.
Closely followed market-watcher Dennis Gartman, the founder and publisher of the Gartman Letter, told CNBC on Wednesday the early week's market gains could continue for the next couple of weeks.
U.S. stock indexes posted their best day since March on Tuesday with gains of more than 1 percent, following a rise in crude oil prices and encouraging reports on the housing market.
"Historically when that happens, we carry through. So I think you're likely to trade better — maybe not today, particularly — but I bet by Friday we're higher and I bet by next week we're higher again," Gartman told CNBC in London.
"Anybody who's short — and there are a lot of smart people who are in fact heavily short — they have to run for cover, and I think it could get ugly," he added.