Vietnam is forecast to remain Asia's fastest-growing nation after India through 2028, supported by exports and infrastructure investments, although heavy public spending may lead to larger fiscal deficits, a senior S&P Ratings official said on Thursday. Hanoi is seeking an upgrade of its sovereign rating to investment grade from at least one major agency by the end of the decade, while also targeting annual economic growth of at least 10% through 2030, backed by investments in hundreds of new large-scale projects launched last year worth an estimated $200 billion.