Donald Trump has built billions of dollars in personal wealth. His employees aren't getting much of it.

The Republican presidential candidate operates an unusually stingy 401(k) plan for his workers, according to government filings.

If you can jump through hoops and endure years of working for Trump, his matching contributions are more generous than average. If you contribute 6 percent of your salary, Trump will kick in 4.5 percent.

But here's the catch. You can't even join the plan until you spend a year as a Trump employee. Call it an apprenticeship.

Then, if you want that matching contribution, you have to wait until the end of a calendar year. Leave—or get fired—in October, and you get nothing.

Even if you stay, Trump's contribution doesn't completely belong to you for six years. That vesting schedule is the slowest allowed under U.S. law.

And if you worked for Trump from March 1, 2009 through June 30, 2012, you were out of luck entirely. Trump, who claimed an $8.7 billion net worth last month, suspended all employer contributions to 401(k)s for more than three years. 

Under Bloomberg's rating system for 401(k) plans, Trump scores a 30 out of a possible 100, lower than all but one of the top 50 companies by market capitalization. It scored one point back in 2011 when Trump wasn't matching contributions at all.

Hope Hicks, a spokeswoman for the Trump campaign, didn't comment in response to questions about the 401(k) plan on Monday. 

The details are revealed in the forms filed annually with the U.S. Department of Labor by the TrumpPayroll Corp. 401(k)/Profit Sharing Plan, and they're worthwhile reading for anyone trying to analyze the business success that's the foundation of the Trump campaign.