What it means
The prefix "deca" means ten, so a decamillionaire has ten million or more. Net worth is the key measure: it adds up assets such as property, investments, business ownership and cash, then subtracts debts such as mortgages and loans.
Someone who owns a $12 million house with a $9 million mortgage is not yet a decamillionaire on that asset alone. In wealth management, the term sits within a ladder of labels that includes millionaire, multimillionaire and centimillionaire (net worth of $100 million).
Banks, advisers and research firms use these bands to segment clients because the needs change as wealth grows. A decamillionaire usually wants more than a standard savings account, such as tax planning, estate planning and specialist investment access.
Definitions vary, which is why you will see different headcounts in different reports. Some surveys count only investable assets (cash and securities that can be sold), while others include the main home or business interests.
Some measure in dollars and others convert from local currencies, so exchange rate movements can shift people in or out of the group. For business owners, reaching this level often comes from a sale or growth in the value of a company rather than from salary.
That makes wealth uneven and sensitive to markets, since the paper value of a private firm may not be easy to turn into cash. For finance professionals, understanding the term is useful when dealing with private clients, lenders and fund managers.
It signals the type of service and the minimum investment size that may apply, such as access to private equity funds that require large commitments. The label is also a reminder that net worth is not income.
A person can be a decamillionaire on paper and still have limited cash flow, particularly if most of their wealth is tied up in property or shares of a private company. For that reason, advisers look at liquidity, spending needs and tax exposure alongside the headline figure.
In practice
Real-world examples.
Example
A software founder sells her company and receives $14 million after tax. She becomes a decamillionaire and hires a wealth manager to plan how to invest, how to pass wealth to her children and how much to give to charity.
Example
A private bank offers a dedicated service team to clients with net worth above $10 million. A property developer with large holdings and moderate debts qualifies for it.
Example
A research firm publishes a report on the number of decamillionaires in a city. The totals rise in a year of strong stock markets and fall when property values drop, which shows how sensitive the group is to asset prices and exchange rates.
Formula
Calculation
Formula: Net worth = Total assets - Total liabilities. Decamillionaire status: Net worth >= $10,000,000.
Worked example: an entrepreneur owns a business stake worth $7,000,000, a home worth $3,000,000, an investment portfolio of $2,000,000 and cash of $500,000. She has a mortgage of $1,200,000 and other loans of $1,100,000.
Total assets = $7,000,000 + $3,000,000 + $2,000,000 + $500,000 = $12,500,000
Total liabilities = $1,200,000 + $1,100,000 = $2,300,000
Net worth = $12,500,000 - $2,300,000 = $10,200,000
Her net worth is $10,200,000, so she qualifies. If her business stake fell in value by $1,000,000, her net worth would drop to $9,200,000 and she would fall below the line.Case study
Seen in the real world.
Ostrander Logistics is a fictional family transport company used here as an illustrative example. The founder, Marcus, owned 80% of the business, a stake an adviser valued at $11 million, and had a mortgage of $600,000 on his house, which was worth $1.4 million. On paper, his net worth was around $11.8 million.
Marcus described himself as comfortably wealthy but short of cash. All of his wealth was in the company and his home, and he drew a modest salary. When a bank considered his application for a private loan, it treated his business stake with caution because it could not be sold quickly.
Marcus eventually sold part of his stake to an investor for $2.8 million, which gave him cash to diversify. This illustrative story shows that a high net worth and high liquidity are different things.
Watch out
Common mistakes.
- Counting assets without subtracting debts. Net worth is what remains after liabilities.
- Assuming a decamillionaire is rich in cash. Much of the wealth is often in property or private businesses.
- Using one definition everywhere. Some lists count only investable assets, and others include homes and business interests.
Questions
People also ask.
Is a decamillionaire the same as a multimillionaire?
A multimillionaire is a looser term for someone with several million. A decamillionaire has at least $10 million.
What comes after decamillionaire?
Centimillionaire, with net worth of $100 million or more, and then billionaire at $1 billion. These are common labels in wealth reports.
Does the term apply only to dollars?
Not strictly. The word is often used with dollars as the standard, but net worth in another currency can be converted at the going exchange rate. Because rates move, someone can cross the line without earning or spending anything.
From the founder's library
Take it further with the book.
Build your financial confidence beyond this definition. Shihan's full-length guide, Accounting Fundamentals, takes the same plain-English approach and turns it into a complete, practical playbook for non-finance managers, business owners and students - with chapter-end quiz answers and presentation slides included.
25% off with code MMHQ25, applied at checkout. Priced in USD - checkout may show the equivalent in your local currency.
View the book and save 25%Related