BRUNSWICK, Maine — Former Gov. Angus King has received more than $350,000 over the past year and a half as a consultant, trust executor, college professor, corporate director, public speaker and author, and he and his wife, Mary Herman, hold millions of dollars in assets that include stocks, bonds and mutual funds.

Meanwhile, King’s Republican and Democratic rivals for Maine’s open U.S. Senate seat have incomes that are notably smaller and less diversified.

The details are contained in financial disclosure reports the candidates had to file with the U.S. Senate Select Committee on Ethics. King filed his report last month and Republican Charlie Summers and Democrat Cynthia Dill finished their reports this week.

The deadline for filing the financial disclosure report was May 15. Candidates face a $200 penalty for filing more than 30 days late.

The length of the reports — which cover Jan. 1, 2011, through the report filing date — speaks to the differences in wealth and income among King and his two rivals.

King’s 25-page report lists 23 sources of non-investment income and 15 pages of mutual fund, stock and bond holdings for King, Herman and their children.

Summers’ five-page report lists his salary as Maine’s secretary of state, his wife’s income from a foundation that awards scholarship money to students attending for-profit colleges, and a handful of stock holdings.

Dill’s eight-page report includes her income as a state senator, her husband’s income as a teacher and an early withdrawal from a retirement fund.

“People have known that Angus was wealthy,” said King campaign manager Kay Rand. “When he was governor, wealth didn’t influence the way he governed, and it’s not going to influence the way he votes in Washington.”

During the nearly 18 months covered by the report, King earned five-figure sums for sitting on company boards, including $67,000 for the Bank of Maine, $18,000 for Hancock Lumber and $25,000 for Woodard & Curran, an international engineering firm with an office in Portland. Campaign spokeswoman Crystal Canney said King resigned from the federally regulated Bank of Maine board in April in order to avoid a conflict of interest.

King also divested his ownership in wind development company Independence Wind in preparation for his Senate run, selling his stake to partner Rob Gardiner. The disclosure report shows that King earned a profit of $69,500 from that transaction. He also had earned $50,000 a year in management fees for three years he spent working on the development of two wind turbine projects, at Record Hill in Roxbury and Highland Plantation in Somerset County.

King also earned almost $40,000 from his Maine state government pension and between $10,000 and $30,000 during the reporting period in rental income from two rental properties in Brunswick and a rental condo on the Caribbean island of St. Thomas.

The value of the assets King and his wife hold in mutual funds, stocks and bonds, including a number of stocks Herman inherited, amounts to millions of dollars, said Canney.

Herman’s stocks include holdings in Apple, Exxon Mobil, Nike, PepsiCo, Nike and Toyota. Her bonds include holdings for Augusta, Bangor, Cape Elizabeth and Kennebunk, along with the Maine Turnpike Authority and the Maine Municipal Bond Bank.

Summers listed just one source of non-investment income: his $72,727-a-year job as Maine’s secretary of state. His report, however, listed just $70,000 in income for all of 2011 and the first six months of 2012.

Campaign manager Lance Dutson said Summers actually earned about $105,000 during the reporting period and the campaign will have to amend the disclosure report.

Summers’ stocks include holdings in Exxon Mobil, Ford, PepsiCo and Wal-Mart. He lists no income-generating properties.

Dill’s financial disclosure lists about $66,000 in non-investment income from her service as a state legislator, an adjunct professor at Southern Maine Community College and an early $30,000 withdrawal from a retirement plan. Dill also reports income as a consultant for Washington, D.C.-based Common Cause, where she used to work, and Friends of the Maine Woods, an advocacy group Dill started to support the location of a national park in northern Maine.

Her only stock market investments appear to be two mutual funds. She also is part owner of a rental condo in Cape Elizabeth and is part owner of a parcel of land in Walpole, N.H.

Independent candidate Andrew Ian Dodge also has filed a disclosure report.

Unsuccessful candidates in the Democratic and Republican primaries also had to file financial disclosures. Those who have filed already include Democrat Matt Dunlap and Republicans Rick Bennett, William Schneider and Bruce Poliquin.