HANOI :Vietnamese conglomerate Vingroup said on Tuesday it had signed a memorandum of understanding with private equity fund JTA Investment Qatar to explore a potential investment of at least $1 billion in electric vehicle maker VinFast. Nasdaq-listed VinFast is pursuing an aggressive but costly expansion strategy in Vietnam, where it can rely on a growing market of nearly 100 million people. The automaker also wants to expand abroad but has so far struggled to attract foreign buyers. Its