The advance put the Dow Jones industrial average and the Standard & Poor's 500 index back into record territory.
The Dow was up 106 points, or 0.7 per cent, at 15,576 at noon (1600 GMT) Thursday. The gains were led by IBM and UnitedHealth.
The S&P 500 was up 10 points, or 0.6 per cent, at 1,691.
The Nasdaq composite rose nine points, or 0.2 per cent, to 3,619. The technology-focused index was held back by declines in Intel and eBay, which reported disappointing results late Wednesday.
Financial stocks were among the gainers. Morgan Stanley rose 5 per cent to $27.89 after reporting a surge in revenue from investment banking and wealth management.