NEW YORK — Hindenburg Research, the financial research firm with an explosive name and a track record of sending the stock prices of its targets tumbling, is taking on one of the world’s richest men. Hindenburg is back in the headlines after last week accusing Indian conglomerate Adani Group of “a brazen stock manipulation and accounting fraud scheme.” It cited two years of research, including talks with former Adani senior executives and reviews of thousands of documents. The Adani Group has blasted the accusations, calling them “a malicious combination of selective misinformation and stale, baseless and discredited allegations that have been tested and rejected by India’s highest courts.” [time-brightcove not-tgx=”true”] Nevertheless, Hindenburg’s scorching allegations have caused the fortune of Adani Group’s founder, Gautam Adani, to slide by more than $34 billion in just a week, according to the Bloomberg Billionaires index.