By Elizabeth Howcroft PARIS (Reuters) -S&P Global has downgraded its rating of the world's largest stablecoin, Tether,​ citing an increase in higher-risk assets in the cryptocurrency's ‌reserves and "persistent gaps in disclosure", the ratings agency said on Wednesday. S&P ‌in 2023 created a new scale from 1 to 5, to assess the risk of various stablecoins - a type of cryptocurrency pegged to mainstream currencies, usually the U.S. dollar. In a research note S&P ⁠said it now rated Tether'‌s token, known a ...