National Australia Bank (NAB) has decided not to fund the Adani coalmine, rail and port facilities on the Great Barrier Reef coastline.
The Korean company LG has also announced it will not buy the company's coal.
Korean electronics giant LG signed a letter of intent with Adani last year to purchase 4 million tonnes of coal from the Carmichael mine. However Adani has now lost one of its two big external customers when the letter of intent expired and was not renewed.