McGinty and Schwartz each took home more than $500,000 in 2012, their tax returns show. McCord reported $333,000 also for 2012, and lent his campaign $1.7 million.
Wolf's preliminary 2013 tax filling reported an adjusted income of $1.3 million.
The wealth of the candidates underscores a disheartening reality, said Chris Borick, a political science professor at Muhlenberg College.
"You don't have to be a billionaire, but you need to have a strong financial portfolio," he said. "The amount of money it would take is prohibitive to the average person. . . . You look at some of these candidates, and it supports the belief that to play in this sphere, you have to be in the highest echelons of income of all Americans."
That perception is often borne out by reality, Borick said. Relatively few middle-class individuals have mounted successful runs for offices such as governor, he said. Besides money, candidates need the ability to take time off from their jobs and potentially gamble large amounts of their savings on their political future.
"We're narrowing the field of talent by nature of this," he said. "Any time you're excluding choices, it's not necessarily the best thing for democracy."
In recent weeks, Corbett, who with his wife reported $200,000 in adjusted income last year, has brought personal wealth to the forefront by making available 10 years of his tax returns. Corbett challenged the Democratic gubernatorial candidates to do the same.
Wolf, a York County businessman whom polls have placed as the Democratic front-runner, has far outspent his rivals by donating $10 million to his own campaign. He came under fire this month after disclosing that part of that money came from a $4.5 million bank loan.
When Schwartz, a five-term congresswoman, raised concerns over the terms of the loan, Wolf said he and his wife, Frances, guaranteed it from M&T Bank with personal assets, including millions of shares of stock in the Wolf Organization, the family-controlled building supply company.
Wolf and his wife also released their preliminary 2013 returns. The couple filed an extension, but reported a preliminary amount of $1.3 million in adjusted income.
McCord, the state treasurer, has spoken of his years of financial uncertainty when his mother was raising him alone in California. His claims drew an attack from a stepbrother, who said McCord was discounting the later role of his stepfather in supporting the family. But McCord has maintained that the experience showed him what it was like to live in fear of poverty.
McCord and his wife, Leigh Jackson, reported the $333,000 in adjusted income in 2012, which included his $118,000 salary as treasurer and $150,000 in capital gains.
McGinty, an environmental official in the Clinton White House who was later secretary of the state Department of Environmental Protection, has also said she understands financial vulnerability. As the daughter of a Philadelphia policeman and a restaurant hostess, she often tells audiences, she was the first in her family to attend college right out of high school.
Now an environmental consultant, McGinty and her husband, Karl Hausker, who also works in the field, reported $895,000 in adjusted income in 2012.
"These personal narratives are a connection to a lot of individual voters, and to the aspirations of many of them as well," Borick said. "Voters see people who have risen to good economic standing, and that inspires them."
McGinty has lent about $300,000 to her own campaign.
Schwartz and her husband, David, reported $560,000 in adjusted income, including her congressional salary and state pension, and her husband's salary as a physician. She has not given money to her own campaign, spokesman Mark Bergman said.
Inquirer staff writer Thomas Fitzgerald contributed to this article.