Gillibrand's early disclosure of her 2018 tax return is a recurring nod to political transparency. She has provided tax returns each year since 2012, midway through her first Senate term, and disclosed older returns dating to 2007, her first year as a New York congresswoman.
"I want voters to know that I am beholden to no one, that my values are not for sale and that I'm working only for you," Gillibrand said in a video posted by her campaign. "We can't fundamentally change Washington unless we can show the American people we are brave enough to do what needs to be done."
The capital loss was carried over from investments made in previous years, campaign spokeswoman Meredith Kelly said. The 2018 return lists only one holding, Wind Crest LLC, a medical services company that is an inactive investment vehicle. Gillibrand's recent Senate financial disclosures have shown a $15,000 to $50,000 investment in the company.
Gillibrand's move comes as many of her rivals for their party's 2020 nomination to take on President Donald Trump have yet to share their own tax return data, even as Democrats continue to slam Trump for not releasing his returns during his 2016 run for president.
Massachusetts Sen. Elizabeth Warren has released 10 years of her tax returns but not her 2018 filing. Other Democratic candidates have yet to share as much tax information. Vermont Sen. Bernie Sanders last month pledged to "sooner than later" make public 10 years of his tax returns, though he has yet to do so. During his 2016 presidential bid, he released just one year of tax returns.
Minnesota Sen. Amy Klobuchar's campaign also has indicated that she will release her tax returns, but it did not commit to a timeline. A spokeswoman for South Bend, Indiana, Mayor Pete Buttigieg, who is exploring a presidential bid, said he will release taxes when or if he formalizes his campaign.
Trump broke with decades of tradition by not releasing his tax filings during his 2016 Republican presidential campaign. He argued that he couldn't release his taxes because he was under an audit by the Internal Revenue Service, but being under audit is no legal bar to a candidate from releasing tax returns.
Associated Press writer Sara Burnett in Chicago contributed to this report.