Unveiling its latest quarterly index of corporate rankings, determined by the amount of favourable stories a company receives, US media consultancy Delahaye said Microsoft retained the top spot.

The company, whose operating systems power 90 percent of computers worldwide, benefited from "news of upward economic performance, a strong product pipeline and corporate partnerships", Delahaye said.

Wal-Mart, the world's largest retailer, stayed second in the rankings, followed by media and entertainment group Time Warner in third.

Wal-Mart has been accused of waging war on trade union representation of its workers, and of giving the worst pay in the retail industry.

But Delahaye said such "high-profile negative coverage" was countered by positive stories on a recent tie-up between Wal-Mart and mail-order video rental firm Netflix, and a marketing drive to bring in richer shoppers.

General Motors jumped five spots to fourth place after a hugely popular price discount programme in the United States overcame negative coverage of problems with the global carmaking giant's financial balance sheet.

"This quarter's index results reinforce the dual reality -- and difficulty -- of working to maintain a positive corporate image while having to operate openly under the lens of the media," Delahaye president Mark Weiner said.

"For example, news coverage of GM's weak financial performance, while negative, was outweighed by positive news about the company's wildly successful price promotions," he said.

The Delahaye corporate reputation index balances how many positive and negative "reputation-driving attributes" are found within each news story.

Those attributes are five-fold: stakeholder relations, financial management, products and services, organizational integrity and organizational strength.

Delahaye's Top 10:

1. Microsoft Corp.

2. Wal-Mart Stores Inc.

3. Time Warner Inc.

4. General Motors Corp.

5. Walt Disney Co.

6. Intel Corp.

7. Verizon Communications Inc.

8. Boeing Co.

9. Goldman Sachs Group Inc.

10. General Electric Co.