A global water-filtration company based in Bothell said Thursday it had successfully raised $25 million in a secondary offering on the London Stock Exchange.

Halosource, which sells water-filtration cartridges to device-makers in India, China and South America, said the capital infusion would allow it to remain financially viable and expand its sales to a huge underserved market.

“We have a significant cushion now in place that takes us well past break-even,” said CEO Martin Coles. “This is a big area to make a difference in.”

Many people in India, China and other developing nations do not have access to clean water. Halosource designs and manufactures HaloPure cartridges filled with bromine-infused beads the company says kills bacteria, viruses and cysts.

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The company, which went public in October 2010, said it will issue 80 million new shares of stock Friday in connection with the closing of the offering.

Halosource’s stock price has been on a rally since late September, when it traded for about 20 British pence on the London Stock Exchange. It closed at 33.50 British pence Wednesday.

Sanjay Bhatt: 206-464-3103 or sbhatt@seattletimes.com