The Dow Jones was up in early trading, rising 71 points, or 0.95%, to 7,593 as of 3:25pm GMT.
The index was helped by large increases in technology and financial stocks, with Citigroup leading the pack, up 9.09% to $2.52.
It was followed closely by Bank of America, up 7.3% to $6.47, and Microsoft, which increased 4.41% to $18.25.
Meanwhile, in London, the FTSE 100 continued its steady climb into the afternoon, rising 3.49%, or 131.24 points, to 3,894, as of 3:30pm.
It was led by the basic materials sector - up 4.04% on the day - with miners Kazakhmys and Xstrata the highest gainers in that sector. The copper mining giant rose 10.08% to 366p, while the Swiss mining company was up 9.71% to 466p.
Barclays, however, reversed its early morning gains to become the biggest loss maker of the day, down 2.15% to 145p.
It was joined by earlier loser Randgold Resources, which slipped 1.32% to £36.50, and Intertek Group, which lost 1.23% to 880p.Investment Week
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