Over the last decade and a half I’ve become relatively proficient at running a small business with the mix of record-keeping and spreadsheets, forecasting and cash flow management. I have no competence to analyze the wealth of an extremely rich person like Donald Trump with all the mixes of assets, leverage, advantageous tax structuring, rates of return in different businesses, etc. But I can read what those who do know these topics very well have written about Trump’s wealth and disclosures. And I can apply simple logic and numeracy.

The following is a list of things I’ve learned about Trump over recent months that make it clear he is worth dramatically less than he claims and think it is a real possibility that he has a net worth of less than $1 billion. None of the ten is definitive or proves he is worth a certain amount now or even that he could not be worth the $10 billion he claims. But taken together they show a chronic exaggeration of his wealth, repeated instances of financial reports that include almost comical efforts to inflate the numbers (like reporting gross revenues as income) and various points where his net worth was estimated with some precision and make it hard to credit how he could now be worth so much today.

So with that, here’s the top 10.

1. In 2004, Timothy O’Brien published TrumpNation. In the course of researching that book, “individuals who worked with Trump and a had a good sense of his finances” thought Trump’s net worth was “$150 to $250 million.” Trump later sued O’Brien for damages for saying he was worth so little. The suit was later dismissed.

2. During the litigation of that lawsuit, O’Brien and his lawyers were able to review a 2005 Deutsche Bank assessment of Trump’s wealth which placed his net worth at approximately $788 million. Deutsche Bank should know. While most big banks have shunned Trump because of his multiple business failures, Deutsche Bank has been Trump’s go-to bank for almost 20 years.

3. In financial filings, particularly with the FEC, Trump routinely overstates his income by reporting business revenue as income or conflating the two numbers. The difference between revenue and income is obvious to anyone who has run a business as small as a lemonade stand. ‘Revenue’ or cash flow is all the money that comes into the business before you subtract expenses and miscellaneous other negative entries. If you subtract the latter from the former you have ‘income’, what you actually take home at the end of the year. A company may have $50 million in annual revenues and be making $25 million profit, just breaking even or losing money hand over fist. Income here is the individual analog to profit for a business entity. Revenue tells you almost nothing about income. The fact that Trump routinely conflates the two numbers is such an elementary and massive effort to inflate the scale of his income that it points to someone trying to massively overstate income and wealth. Just how much is a good question. In this March 2016 article, Shawn Tully of Fortune tried to parse Trump’s filings and estimate just how much Trump was inflating his income.

4. Trump refuses to release his income tax returns and is knowingly incurring substantial political damage for failing to do so. He would only do so if they contained information he very, very much does not want to see made public.

5. Trump repeatedly received a New York State tax credit that is restricted to married couples making no more than $500,000 a year in federal adjusted gross income. Trump himself and later New York City said Trump had received the credit in error. But the the City of New York very conspicuously did not say that it was because Trump made more than that much money a year. Every year, the City cross references recipients with state records which show the income of recipients.

6. During the research for O’Brien’s book he received estimates of Trump’s wealth ranging from $250m to $788m. Trump himself originally told O’Brien he was worth between $4b and $5b before dramatically revising down his estimate to $1.7 billion the same day. If we take $250m, $788m and $1.7b together and rough average them out we can get around $1 billion circa 2004/05. Today Trump claims he is worth $10 billion. This would require a tenfold run up in Trump’s wealth over roughly a decade. Even if we take Trump’s own estimate of $1.7 billion it would require a five fold run up over a decade. The problem is that Trump hasn’t done anything over that period that would account for that kind of wealth accumulation. Trump does very few major building projects these days and the few he does he does mainly with other people’s money. After the bankruptcy crises of 25 years ago, Trump shifted his business model from high profile real estate development to licensing and television. He licenses his name for hotels, buildings and golf courses on the high end and steaks, water, ties and more on the low end. This probably generates a massive amount of income for us mortals. But not many billions of dollars over a decade. There’s also been a major run-up in the value of Manhattan real estate over this period. But not nearly enough to get Trump from $1 billion to $10 billion. A year ago industry insiders were highly skeptical when Trump claimed that he had made $213 million for 13 years of The Apprentice. But even if we take Trump’s word for it, that’s still not remotely the sum of money to put in a dent in the run up of wealth he claims.

7. Trump has gotten a good deal of ridicule for efforts like Trump Steaks, Trump Water, Trump University and other similar ventures. But it is difficult to believe someone worth $10 billion would play around with such penny ante gambits. Perhaps it’s just ego and the desire to maximize the return on his ‘brand’. But the litany of these failed ventures, the possible return on which would be a few million dollars at best, suggests someone with far, far fewer assets and wealth than Trump claims.

8. During the presidential campaign, despite Trump’s claim to be self-funding his effort, Trump has made a number of moves that suggest expenditures even in the tens of millions of dollars represent a real strain on his finances. Trump’s self funding was almost entirely loans to his campaign. He could make those into simple contributions with the stroke of a pen. And yet he still hasn’t ruled out asking Republican mega-donors to reimburse him for the cost of his self-funded primary campaign. $10 billion is 10,000 million dollars. Even if much of his wealth isn’t liquid, 40 million dollars should be a minor expense for someone with that scale of wealth.

9. Yesterday Trump frenemy Mark Cuban told a radio host that he questions whether Trump is even a billionaire, based on the plethora of low profit businesses Trump is in and his financial disclosure that shows very few liquid assets relative to a purported $10 billion net worth. Cuban would not be above tweaking Trump on a sensitive topic. Real estate is inherently illiquid. But having no more than $165 million in liquid assets is very little for someone worth $10 billion. With regards to Trump’s wealth, Cuban told Business Insider that “liquidity is a good proxy for relative worth” and that “you can’t lie about cash, stocks and bond values.” Even if Cuban is just jerking Trump’s chain or underestimating the amount of wealth Trump has tied up in real estate, it does point to the strong possibility that even if Trump is worth something close to what he claims the amount of cash he is able to do anything with is very limited, as billionaires go.

10. Nobody who is in the business of estimating the wealth of the extremely rich believes Trump is worth anywhere near $10 billion. On the high end is Forbes which pegs the number at $4.5 billion. Bloomberg puts the number at $2.9 billion. Fortune says he’s worth $3.9 billion. These estimates are all dramatically lower than what Trump claims. But the Fortune and Forbes estimates put Trump comfortably into the billionaire category.

So even if Trump comically and needily exaggerates his wealth by three or four fold, why should we question whether he might have a net worth of under $1 billion, the key diagnostic indicator for a diagnosis of Low B? We should take each of these estimates seriously. They come from people who know a lot about doing this, certainly more than I do. But remember, Trump sues people who peg him at really (relatively) low numbers. And a key point to consider is that what everybody says is that Trump’s disclosures and structuring of his assets is extremely opaque. Key variables they have to use are still self-reported and thus (from Trump) highly questionable. How much of a building does he really own? How much debt is he carrying, how much income does he actually make on a given property or licensing deal. Because these are all mainstream business publications, which need to appear and be fair, and avoid getting sued, they tend to make generous or at least reasonable average estimates on various fronts. They’re not in a position to plug really adverse assumptions into all the blank variables. So why should we? Maybe we should and maybe we shouldn’t. But there’s plenty of evidence of Trump’s extreme need to inflate his wealth and his willingness to lie with complete abandon. So I think there’s at least a very decent chance that even these estimates substantially over-state Trump’s wealth.

As all of these analysts have argued that while a tax return does not report wealth, a verified look at his income would give us a much, much clearer view of whether Trump is actually worth even a billion dollars.