There is a question every investor should be able to answer without looking at a statement. What is your largest position?
Most people will name a company or a fund. For a growing number of portfolios, the honest answer is neither. It is a single idea. Artificial intelligence.
What the Index Has Become
The broad US market is no longer the diversified instrument most people picture when they hear the word index. As of September 2026, the seven largest technology companies make up roughly a third of the S&P 500, and the ten largest names account for roughly forty percent of it, the highest level of concentration in the index's history. Analysts now expect artificial intelligence infrastructure spending to drive roughly half of the index's earnings growth this year, and the companies at the centre of the build out have committed more than USD 600 billion of capital spending in 2026 alone.
None of those numbers is a criticism. They describe what the thing has become. An investor who buys the index today is not buying five hundred loosely related businesses. They are buying a large wager on one technology cycle, wrapped in the packaging of diversification.
A Decision Nobody Made
Here is the part worth sitting with. Almost no one holding that wager decided to make it.
I have written before that concentration is not a dirty word. A concentrated position, taken deliberately, sized to circumstances, and watched with discipline, is one of the most legitimate tools in investing. But that argument rested on one word doing all the work. Deliberately.
What has happened inside the index is different. The concentration arrived by drift. Prices rose, weights followed, and a portfolio that was diversified when it was purchased quietly became something else while nobody was looking. The exposure may even turn out to be the right one. The problem is that for most investors it was never a decision. It was a side effect.
There is a real difference between a bet you placed and a bet you woke up holding. The first comes with a rationale, an entry point, and a clear sense of what would prove you wrong. The second comes with nothing but the hope that it works out.
Convention and Conviction
There are two ways to own anything, and the difference between them is the difference between those two bets.
Convention is ownership without a reason. It is whatever sits in a portfolio because it was the default. The allocation that came with the model. The fund everyone holds because everyone holds it. The position that has survived ten years not because anyone re-examined it but because removing it would have required a conversation. Convention never has to defend itself, because nobody ever asks it to. I have written at length about why convention fails; the short version is that it offers one great comfort. When convention is wrong, everyone is wrong together.
Conviction is ownership with a reason you can say out loud. A position held with conviction has a job to do, a size that was chosen rather than inherited, and a standing answer to the question of what evidence would send it away. Conviction is more expensive than convention. It demands work before the purchase and honesty after it, and it sometimes means standing apart from the crowd during the very stretch when the crowd is being paid.
Run the index's AI weighting through that lens and the point sharpens. The exposure itself is neither good nor bad. Held with conviction, at a size someone chose for reasons they can state, it is a decision. Held by convention, it is the largest position in the portfolio, and it has no owner.
The Question That Is Not Yours to Answer
Is artificial intelligence a bubble? You will find brilliant, well informed people on both sides, each armed with data, each fully confident. The build out is either the foundation of the next economy or an expensive loop of companies funding one another's spending, and the record of past technologies offers no comfort in either direction. Transformative inventions and terrible investment outcomes have coexisted before. So have loud skepticism and generational opportunity.
The liberating truth is that you do not need to answer this question. Nobody does, except the people paid to hold an opinion in public. The demand that you call the top, or call the opportunity, is the same trap as the demand that you beat the market. It hands your financial life to a question you cannot control and takes your attention away from the ones you can.
The Question That Is
The question that belongs to you is smaller and far more useful. Do you know how much of one story you own?
Not roughly. Actually. Across the index funds, the pensions, the accounts that have drifted for a decade, the employer stock, the holdings you stopped watching because they kept going up. Added together, what does your exposure to this one cycle amount to? Was it sized to your circumstances, your timeline, and the job your capital has to do? And if the story stumbles for three years before it succeeds, or succeeds for three more years before it stumbles, does your plan survive both versions?
An investor who can answer those questions can hold a large position in this cycle with a clear conscience. An investor who cannot is not really invested. They are along for the ride.
How We Approach It
The portfolios I manage are built position by position, from conviction, not convention. Every exposure has to clear the test above: a job to do, a size that was chosen, a rationale that can be stated out loud, measured against the client's actual circumstances rather than against whatever weight the index happens to be carrying. And because what was true at entry must still be true to remain, that exposure gets questioned on purpose, regularly, while it is working. It is easier to hold than to question. We choose to question.
None of this tells you whether the current cycle ends in vindication or regret. Nobody can. It tells you something more durable. Whatever you own should be owned on purpose. The size of every bet should be a choice, made in daylight, by someone who knows what your money is actually for.
The market has placed an enormous bet on one idea. That is its business. Yours is making sure that whatever share of it you carry is a bet you actually placed.
Forward With Purpose.
Ross Sikora