If the value of a major asset increases, the estimated net worth can rise.
If its value falls, the estimated net worth can decline.
That is one reason why billionaire rankings can change rapidly.
The Forbes data from 2026 provide a dramatic example. Musk's estimated fortune moved from approximately $1.1 trillion when SpaceX began trading to a substantially lower figure later in the year as SpaceX's valuation and other factors changed.
The $100 doubling experiment, by contrast, assumes something completely different.
It treats every dollar as liquid cash.
That is another simplification that makes the thought experiment useful mathematically but unrealistic financially.
Exponential Growth Is Everywhere
The deeper lesson is not about gambling.
It is about recognizing exponential patterns.
Compound interest is perhaps the most important financial example.
If money earns returns and those returns remain invested, future growth can occur on both the original principal and previous returns.
For example, suppose someone invests $10,000 and earns a hypothetical 7% annual return, with all returns reinvested.
The first year produces approximately $700.
The next year's return is calculated on a larger balance.
The amount of growth therefore gradually increases.
This is the basic principle behind compound growth.
It does not mean that investments actually double at regular intervals. Real markets fluctuate, returns are uncertain and fees, taxes and inflation matter.
But mathematically, compounding illustrates the same fundamental concept: growth can build upon previous growth.
That is why time can be one of the most powerful variables in investing.
The difference between earning a return once and repeatedly reinvesting returns can become substantial over long periods.
The Rule of 72
There is even a simple mathematical shortcut for thinking about doubling in finance: the Rule of 72.
Wolfram MathWorld explains that the approximate doubling time for compound growth can be estimated by dividing 72 by the annual percentage growth rate.
For example, at an assumed 8% annual growth rate:
72 ÷ 8 ≈ 9 years
So an amount growing at approximately 8% per year would roughly double every nine years, assuming the rate remained constant and ignoring complications such as taxes and fees.
Again, this is not a promise of investment performance.
It is simply a mathematical approximation that helps people understand the relationship between growth rates and doubling time.
Compared with the blackjack thought experiment, the difference is obvious.
Blackjack tries to compress doubling into individual events.
Compound growth spreads the process over time.
One approach requires an extraordinary sequence of successful bets.
The other relies on repeated returns accumulating over many periods.
Why Exponential Growth Often Looks Slow at First
One of the most important lessons from exponential growth is that the early stage can be misleading.
Imagine watching the $100 bankroll after just five successful doubles.
It has reached only $3,200.
That does not look remotely close to a trillion dollars.
Even after ten doubles, the total is just $102,400.
Someone observing only the first few stages might reasonably conclude that the process is not particularly impressive.
But the growth curve has not changed.
The same doubling rule continues.
At 15 doubles, the amount is approximately $3.28 million.
At 20 doubles, it is approximately $104.86 million.
At 25 doubles, it is approximately $3.36 billion.
At 30 doubles, it is approximately $107.37 billion.
The final four doublings then take the hypothetical balance to approximately $1.718 trillion.
This is why exponential processes can surprise people.
The dramatic growth tends to occur after the process has already been running for a while.
The Biggest Problem With the All-In Strategy
There is another mathematical lesson hidden in the blackjack example: growth rate and risk are not the same thing.
An all-in strategy can produce spectacular theoretical growth when everything goes right.
But it also creates catastrophic downside.
If the entire bankroll is placed on every hand, the strategy has essentially no tolerance for failure.
A single loss destroys the accumulated balance.
This is fundamentally different from the idea of sustainable wealth creation.
The United Kingdom Gambling Commission specifically identifies patterns such as chasing losses, escalating gambling activity and erratic betting as indicators that can be associated with gambling-related harm. Its responsible-product guidance also says gambling products should not actively encourage customers to increase their stake, chase losses or continue gambling after deciding to stop.
That is important context because the mathematics of doubling can be psychologically seductive.
Someone might look at the sequence:
$100 → $200 → $400 → $800 → $1,600...
and focus entirely on the potential upside.
But probability requires looking at the other side of the equation.
The sequence can also become: