Federal tax cuts proposed by the US could cost the government of Guam up to $US70 million in lost revenue.
The proposed cuts recently passed the US House of Representatives and await passage of the Senate.
The Guam Daily Post reported the projections might force the Guam government to break away from mirroring the federal tax code.
The director of the Guam Department of Revenue and Taxation, John Camacho, said the government could lose between $US40 and $70 million in corporate taxes.
The bill also proposes the first $12,000 for each individual and $24,000 for each couple's annual income would be tax-free.
The Senate is expected to vote on its draft after Thanksgiving.