HONG KONG – An ambitious Pacific Rim trade deal anchored by the U.S. promises to boost the economies of its 12 participating countries by opening their markets to one another, but not all the gains will be spread evenly. Among the biggest winners of the Trans-Pacific Partnership is Vietnam, where booming garment and shoe industries are poised to benefit from the elimination of tariffs in the United States and other major importing nations. Experts say Japanese car and auto parts makers and Malaysia’s electronics and semiconductor industry will also benefit from the trade deal, which was agreed on Monday after more than five years of negotiations. The pact, which still needs ratification from individual countries, aims to liberalize commerce and tighten labor and environmental standards across member nations that account for two-fifths of the world economy. The Trans-Pacific Partnership is central to President Barack Obama’s policy of greater engagement with Asia to offset rising Chinese influence in the region.