Former Hewlett-Packard CEO Carly Fiorina speaks at the First in the Nation Republican Leadership Conference in Nashua, New Hampshire, United States, in this file photo taken April 18, 2015. [Photo/Agencies]

Fiorina, 60, chose the venue of a nationally broadcast morning network news show to announce her candidacy Monday, and she also posted a video. The former chief executive of Hewlett-Packard Co, appearing on ABC's "Good Morning America," said she understands "executive decision-making."

She also directly criticized Democrat Hillary Rodham Clinton, the front-runner for her party's nomination.

"I have a lot of admiration for Hillary Clinton, but she clearly is not trustworthy," Fiorina said, after confirming her plans to seek the presidency. She went after Clinton by name when asked, citing what she called a lack of transparency on a number of fronts, including the deadly 2012 attack on an American embassy in Benghazi, Libya, Clinton's use of a private email server while secretary of state and foreign donations to the Clinton Foundation.

Fiorina has a resume more likely to draw support among the Republican establishment than Carson. She became a prominent figure in Republican politics in 2010, when she ran for Senate in California and lost to incumbent Sen. Barbara Boxer.