Kaine is serving as Hillary Clinton's running mate. Image source: HillaryClinton.com.

Much like Republican Vice Presidential nominee Mike Pence lacks even a fraction of the wealth of running mate Donald Trump, Democratic VP candidate Tim Kaine has much less money than Hillary Clinton, who tops the ticket.

Of the four candidates representing the presidential tickets for both parties, only Pence has filed a full financial disclosure with the Federal Elections Commission (FEC). That form showed the Republican VP nominee had less than $15,000 in the bank, somewhere between $500,000 and $1 million in a pension fund, and hundreds of thousands in student loans on behalf of his children,

Kaine, like Clinton and Trump, has not filled out a similar FEC disclosure, but he has made his 2015 tax return available. along with his returns from the nine years before that. Those documents don't paint a full picture of the junior senator from Virginia's wealth. but it shows a lot of pieces of the puzzle.

Kaine, who filed jointly with his wife, Anne Holton, who was Virginia's secretary of education until she stepped down recently, reported income of $313,441 for 2015, according to The New York Times. In 2015, the senator and his spouse made almost all of their income from their combined salaries, with under $2,000 coming from investment income.

How much is Tim Kaine worth?

Kaine has spent the last over 20 years in public service. His first elected office came in 1994, when he served as a city council member in Richmond, Va., where he later became mayor. He followed that up by being elected lieutenant governor of his home state in 2002 and then governor in 2006. He became Virginia's junior senator in 2012.

In the nine years of tax returns Kaine provided, starting with 2006, the VP nominee and his wife reported income of $178,343 (2006), $181,707 (2007), $194,231 (2008), $175,955 (2009), $320,022 (2010), $263,910 (2011), $156,475 (2012), $264,357 (2013), and $314,398 (2014).

Those are very solid numbers compared with what the average American earns, but they pale in comparison with the $10.74 million Bill and Hillary Clinton earned in 2015, and they're a rounding error on the $28.3 million the pair made the previous year.

Kaine doesn't disclose an overall net worth, and he probably has considerable pension and retirement accounts, having spent so much of his life as an elected official. Insidegov.com, which tracks net worth for elected officials, placed Kaine's at $1.45 million as of 2014, noting that number made him "slightly wealthier than the average member of Congress and ninth among all members from Virginia."

He's going to get richer (if he wants)

Kaine has a modest net worth compared with many well-known politicians, with most of it probably coming from retirement benefits he earned while in office, similar to Pence. But, as Clinton's running mate, whether he wins or loses he should ultimately be able to increase his net worth through speaking engagements and a book deal.

Of course, if he wins, those things could be years away -- perhaps as many as 16 years if he were to win two terms as VP and two as president. But ultimately, being the running mate of the first woman nominated for president in a major political party should pay off for Kaine. Even in losing there would be book deals, potential TV gigs, and other ways to make money should Kaine so desire.