The US Commerce Department today says it's made a preliminary decision to impose tariffs on solar panels imported from China, and will make a final decision in June.

Because China is unfairly subsidizing solar production, they say, the Commerce Dept has ordered U.S. Customs and Border Protection to collect tariffs ranging from 2.90 percent-4.73 percent, retroactive for 90 days before the ruling.

It seems that Chinese solar firms are being charged different tariffs. Suntech is being charged 2.9 percent, Trina Solar 4.73 percent and all others 3.61 percent, based on the subsidies they receive, reports Bloomberg.

It's a victory for the Coalition for American Solar Manufacturing, which filed a petition for the tariffs with the Commerce Department and International Trade Commission last year. But they asked for tariffs of 100 percent.

The group also claims Chinese solar companies are selling panels at a loss to take over the market. The Commerce Department will rule on that separately in May.

Many in the solar industry believe it will have minimal impact, and expected higher tariffs - as much as 10 percent.

The market rewarded Chinese solar companies with 12 percent increases in share prices.

After the Commerce Department makes its final decision, the International Trade Commission will then come to its own conclusion, probably in July.

The push for tariffs caused a rift in the solar industry. Installers, who have been having banner years because of low prices, are against the tariffs.

China has said it would launch its own investigation into US support for solar companies.