A plan to raise $500-million through an initial public offering of the fund next month “is a very shady deal and I’m saying, if I become president, I will not respect that agreement,” Mahama, the presidential candidate for the National Democratic Congress, said in a broadcast on his Facebook page. “It is a theft of Ghanaians’ royalties made to benefit just a few people.”

Mahama’s statement means he will take all legal steps to have the deal canceled, James Agyenim-Boateng, the spokesman for his campaign, said by phone.

Africa’s biggest gold producer wants to use the IPO to take advantage of soaring prices for the metal. The fund will be structured to pay dividends from the government’s income from gold operations and be listed in London and on the local bourse.

The fact that the special purpose vehicle created to manage the fund registered is Jersey, a tax haven, is an attempt to hide the identity of the investors, Mahama said.

“We will not accept that agreement, we will not accept that government of Ghana should invest our royalties in an offshore tax haven,” he said.

Mahama lost power to President Nana Akufo-Addo of the New Patriotic Party in the 2016 election and the two men face off in a third consecutive poll this year. The two parties have dominated Ghanaian politics for decades.