SAO PAULO – Investors in Brazil's Vale have overwhelmingly agreed to swap their preferred stock into common shares, handling the world's No 1 iron ore producer a victory in a plan that will give equal votes to all shareholders and limit government meddling.

In a Thursday securities filing, Vale said a total 1.42-billion preferred shares, or the equivalent of over 72% of that class of stock in circulation, joined the plan, topping the minimum 54.09% threshold set to approve a share conversion plan.

According to the filing, the results are preliminary and a definitive outcome of the share conversion will only be known late on Friday, the filing said. Management at the Rio de Janeiro-based behemoth will discuss the matter at several conference calls on August 14.

The change represents a milestone in a country long hobbled by corporate governance abuses and reorganisations that hampered minority investors in most cases. Reuters reported the plan on January 19, citing people familiar with it.

The plan puts a limit to the meddling of politicians in Vale - an aspect that weighed on the company's stock during former President Dilma Rousseff's five years in office. Still, the government will keep a golden share, allowing it to fend off hostile takeover attempts and shape strategic decisions.

By merging Vale's different classes of stock into a single, common one, the miner could lure more Asian investors and specialised mining and metals funds as shareholders, CFO Luciano Siani told the Reuters Latin American Investment Summit on Monday.

A first phase of the plan had been approved by shareholders in June. Thursday's vote is key to raise awareness among global investors of the benefits of a company with dispersed share ownership, no controlling bloc and with increased transparency over decision-making.

Common shares and Vale's American depositary receipts - which will replace the company's preferred stock - are up about 30% and 34%, respectively, this year.

Currently, seven of Vale's top-ten stockholders are US-based funds, with the other three based in Europe, according to Thomson Reuters data. None of them are mining-only industry funds.

Increased transparency also could help increase Vale's existing shareholder base from about 200 000, Siani said, noting that it was about 500 000 a decade ago.