The president and his deputy submitted their declarations to the Code of Conduct Bureau on Thursday though the figures filed were not available immediately, Buhari's spokesman Garba Shehu revealed.
Buhari, who took office on Friday, has promised to fight the corruption crippling Africa's biggest oil producer. He said every public officer in his government must obey the law by declaring their assets on assuming office and again on their departure.
Former President Goodluck Jonathan in 2012 condemned a clamor for him to publicly disclose his worth. He said his refusal was "a matter of personal principle ... and I don't give a damn about it, even if you criticize me from heaven."
Jonathan added at the time that he could be investigated when he left office. But this week he argued that any corruption investigation of officials in his government would amount to a witch hunt unless the conduct of officials in two previous administrations was also scrutinized.
Buhari said in his inauguration speech Friday that there will be no witch hunt. On Saturday, amid fears his new government would block potential suspects from fleeing the country, he said no previous office holders are barred from leaving Nigeria.
Conduct Bureau chairman Sam Saba later clarified that Jonathan had declared his assets as required by law, but not publicly. That was done while Jonathan was the deputy president, before he became president in 2010. Lawyers argued the point and critics said Jonathan's refusal was another indicator of the impunity that reigned under his administration.
Jonathan's massive rejection at the polls in March was caused in part by his government's involvement in a series of ever more colossal corruption scandals. The most egregious charges came from the then governor of the Central Bank, who disclosed that some $20 billion went missing over 18 months from the federal petroleum account. A limited independent forensic audit has failed to resolve the controversy.