91% of my portfolio is one stock

The position

Ninety-one percent of my brokerage account is Tesla. The other nine percent is SpaceX. That is not a diversified portfolio. It is barely a portfolio. It is one bet with a rounding error attached to it.

Every rule I have read says do not do this, and I have read them. I did it anyway, and not because I think the rules are wrong. It is that most of them are written for someone whose constraint is not mine.

What I have that a fund manager does not is time. I am seventeen. I do not need this money in five years or in ten, and nobody can redeem from me at the bottom. A 40% drawdown is a discount if you are still buying every month and a catastrophe if you have to sell in the spring. I am in the first group and I plan to stay there for a very long time. So I buy the same amount on the same day every month, and I try not to look at the price while I do it.

The case against me

Before any of the bullish part, the honest part. I keep a research file on this company. Here is what my own notes say, and none of it is flattering.

• Deliveries have fallen three years running: 1.81M in 2023, 1.79M in 2024 (the first annual decline since 2011), then 1.64M in 2025. Morningstar models a fourth straight decline in 2026.[S-05]
• Tesla lost the global EV crown to BYD in January 2026, after an 8.6% annual sales decline.[S-06]
• Morningstar reads the stock as “nearly priced for perfection.” Their argument is that the price already assumes a better robotaxi outcome than their own base case, which has a full rollout in 2027 to 2028, later than Tesla guides.[S-05]
• The Q1 2026 earnings beat was not as clean as the headline. Tesla’s own shareholder deck named one-time warranty and tariff benefits as the single biggest driver of operating income growth.[S-08]
• A Yale-authored NBER working paper estimates that Musk’s political activity cost Tesla between 1 and 1.26 million vehicles from October 2022 to April 2025. It is a working paper and the magnitude is contested. The direction is not.[S-07]
• The stock closed near $311.21 on July 31, 2026, around its lowest level since August 2025.[S-04]

If that list were the whole picture, nobody should buy this stock. I wrote that list. I buy the stock anyway. The rest of this is why.

Why I buy anyway

Tesla has not traded as a car company for years, and pretending otherwise is how people lose this argument in both directions. Bears point at deliveries and conclude the company is dying. Bulls point at autonomy and refuse to look at deliveries at all. Both are describing one half of a company that is deliberately trying to become something else.

The car business is the funding mechanism. It generates cash, it keeps the factories warm, and it is not the thesis. The thesis is four bets: autonomy sold as software, a robotaxi network, Optimus, and energy storage.

The delivery decline and the robotaxi story are not two separate facts. They are the same fact. Tesla is winding down Model S and Model X production and converting Fremont capacity toward Optimus. A company harvesting its legacy line to fund the next one looks exactly like a company in decline, right up until the moment it does not. I could be wrong about which of those two I am looking at. That is the crux, and I would rather name it than bury it.

What makes the concentration defensible to me is not confidence, it is homework. I would rather hold one company whose filings I have actually read than ten I picked because a list told me to.

What Cathie Wood’s $2,600 actually says

ARK Invest has a $2,600 price target on Tesla.[S-01] It gets quoted constantly, and almost always without the parts that decide what it means. So here are all of them.

• It is a 2029 target, not a call on next year.
• It is the expected case of a Monte Carlo simulation, not a point forecast. The same model puts a 25% chance at $2,000 or below and a 25% chance at $3,100 or above.[S-02]
• It implies a market capitalization above $9T+.[S-03]
• It assumes 88% of Tesla’s enterprise value comes from robotaxi, and only 9% from selling cars.[S-02]

Measured against a $311 stock, even ARK’s bearish quartile is about 6.4x and the expected case is roughly 8.4x. That should not read as encouraging. It should read as a measure of how extraordinary the assumptions are. A model that needs 88% of the value to arrive from a business currently operating a few dozen cars is not really a forecast. It is a detailed description of one specific future.

Wood has reaffirmed the target through a drawdown of roughly 40%, calling autonomous ride-hailing an $8 to $10 trillion opportunity and the market “winner take most.”[S-03]

I do not hold the $2,600 number. I hold the direction. If ARK is off by half, I have still done well. If ARK’s robotaxi assumption is simply wrong, then the answer is not a smaller number, it is a completely different number, and I would rather have written that down in advance than explain it afterwards.

What would prove me wrong

A thesis that cannot lose is not a thesis. Here is what I am watching, written down now so I cannot quietly move the goalposts later.

• Robotaxi is still a few dozen vehicles in one or two metros at the end of 2027.
• The FSD take rate does not meaningfully move even after an unsupervised release.
• Optimus keeps slipping its production milestones through 2027.
• Deliveries fall a fourth and fifth straight year with no autonomy revenue arriving to replace them.
• Margins keep compressing while capital spending climbs, and the cash position stops being comfortable.

If three of those are true by 2028, I was wrong. I will say so here, on this page, instead of deleting it.

The disclosure

None of this is advice. I am seventeen, with a custodial account, a monthly transfer, and an obvious incentive to believe my own argument. If you came here to decide what to do with your own money, read the case against me twice and the case for me once.

Sources

1. [S-01]ARK Invest's $2,600 Tesla target for 2029
2. [S-02]The target is a Monte Carlo expected case: 25% below $2,000, 25% above $3,100
3. [S-03]Wood reaffirms $2,600 through the drawdown: “winner take most”
4. [S-04]TSLA price and recent range
5. [S-05]Morningstar: the stock is “nearly priced for perfection” on robotaxi
6. [S-06]Tesla surrenders the global EV crown to BYD after an 8.6% annual sales decline
7. [S-07]NBER w34413, “The Musk Partisan Effect on Tesla Sales” (working paper)
8. [S-08]Tesla Q1 2026 results, SEC 8-K Exhibit 99.1

FIGURES CHECKED 2026-08-03. PRICES FROZEN AT JULY 31, 2026 SO THE SENTENCES AROUND THEM STAY TRUE.