BY BRADLEY DAVIS

NEW YORK” The euro dropped sharply, hitting a fresh 10-month low against the dollar, as sovereign-debt concerns in Greece and Portugal rattled investors.

Fitch Ratings added to the euro’s woes, downgrading Portugal’s credit rating by one notch and issuing a negative outlook for a nation that also struggles with massive deficits and unimpressive growth prospects.

Meanwhile, the International Monetary Fund could now lead a rescue package for debt-strapped Greece, according to reports, after euro-zone leaders had earlier insisted on an in-house solution, batting away suggestions of IMF involvement.

Concerns about Greece’s pressing financing needs, along with the high fiscal deficits …