NEW YORK (AFP) - Wall Street finished higher Wednesday for the third straight session, shrugging off global growth worries in expectation the European Central Bank will announce aggressive stimulus measures Thursday.

Strong earnings by Netflix and UnitedHealth buoyed some of the trade, while IBM shares sank on its poor fourth-quarter report.

The Dow Jones Industrial Average finished up 39.05 points (0.22 per cent) at 17,554.28.

The broad-based S&P 500 added 9.57 (0.47 per cent) at 2,032.12, while the tech-rich Nasdaq Composite gained 12.58 (0.27 per cent) at 4,667.42.

Eyes were on the ECB's policy meeting Thursday, with multiple inside-source reports all but convincing the markets that it would embark on a quantitative easing program of 50 billion euros (S$77 billion) a month for purchases of sovereign bonds, to keep longer-term interest rates low.

"They basically leaked the package for tomorrow, so some of the surprise for tomorrow got in the tape today," said Mace Blicksilver, director of Marblehead Asset Management.

Blicksilver said earnings surprises like that of Netflix also fueled the buying.

Netflix shares soared 17.3 per cent after reporting strong profit gains and that its membership rolls expanded by 4.3 million to 57.4 million in the fourth quarter. The streaming video firm said they expect to top 61 million subscribers by the end of the current quarter.

Leading healthcare group UnitedHealth beat expectations for earnings in its fourth quarter, driving its shares up 3.5 per cent.

That offset the impact on the Dow of the 3.1 per cent fall in IBM's shares. The computing giant reported another poor quarter. Revenues in all its markets fell for a total decline year-on-year of 12 per cent to US$24.1 billion (S$32 billion). Earnings per share were off 3.8 per cent to US$5.54, still better than what analysts expected.

"We are making significant progress in our transformation, continuing to shift IBM's business to higher value, and investing and positioning ourselves for the longer term," said Ginni Rometty, IBM's chairman, president and chief executive.

Warren Buffett's huge investment firm Berkshire Hathaway, the largest shareholder in IBM, took collateral damage, falling 1 per cent.

Microsoft sagged 1 per cent as it unveiled the upcoming Windows 10 operating system, which aims to harmonize the diverse array of connected gadgets in people's lives.

Big online services also propelled the indices. Alibaba added 3.35 per cent, Amazon 2.8 per cent and Google 2.3 per cent.

Bond prices fell. The yield on the 10-year US Treasury rose to 1.85 per cent from 1.81 per cent Tuesday, while the 30-year jumped to 2.44 per cent from 2.40 per cent. Bond prices and yields move inversely.