​Filing shows Hillary Clinton earned at least $6.4 million in 2015

Last Updated May 17, 2016 11:20 PM EDT

NEW YORK, NY Hillary Clinton earned more than $6.4 million in 2015, according to a personal finance disclosure form released by her presidential campaign late Tuesday.

Clinton's main source of income last year -- more than $5 million -- came in the form of royalties from her book, "Hard Choices," which was published in 2014. The former secretary of state also made six paid speeches during the first three months of 2015 before announcing her run for president, for which she earned more than $1.4 million.

eBay Inc. paid Clinton $315,000 for a single speech in San Jose in March.

Bill Clinton also made 22 paid speeches last year, the form shows. For each speech, the former president was paid between $181,250 and $300,000. In all, Bill Clinton earned more than $5 million in 2015.

The release of Clinton's personal finance disclosure form comes just after Donald Trump, the presumptive Republican nominee who Clinton is likely to face in the general election, issued a press release stating that he had filed his own disclosure document with the Federal Election Commission showing that Trump's net worth is "in excess of $10 billion dollars."

Alongside her disclosure, Clinton's deputy communications director called on Trump in a statement to release his tax returns.

"Despite Donald Trump's boasting, submitting his Personal Financial Disclosure form is no breakthrough for transparency," said Christina Reynolds. It is a legal requirement for anyone running for president. The true test for Donald Trump is whether he will adhere to the precedent followed by every presidential candidate in the modern era and make his tax returns available, as Hillary Clinton has done."

Last year, Clinton posted eight years of tax returns, covering 2007 to 2014, on her website.