[Profit and Loss Glasses] Tesla stock down 2% on flying car. Loss for someone holding 1 million yen in S&P 500 is about 320 yen
I was looking at the news through my profit and loss glasses.
“Tesla’s flying Roadster, car levitates using air power; stock price falls 2%”
I think many people have seen the video. A sports car drove vertically up a wall-like surface and floated in the air by blowing out air. Honestly, my glasses and my mouth were both left wide open.
[embedded content]
Even so, the stock price fell by about 2% the next day.
There were two things that caught my attention. Why did the stock price fall after such an announcement? And, how much did the investment trusts of people who don’t hold Tesla stock directly move?.
1. The day after the announcement, the stock price started high and ended low
On October 15, Tesla unveiled its new “Roadster” sports car at a SpaceX test site. According to Nikkei reports, the details are as follows.
-
It sticks to the ground with fans on the bottom of the car, allowing it to drive upside down with up to 2G of force
-
It has four thrusters blowing high-pressure air at the back of the car and six on the sides, using technology from SpaceX rocket landings
-
Zero to about 97 km/h in less than a second
-
Production is scheduled to start in 2028. It cannot be driven on public roads at the moment
-
The reservation fee is $50,000 (approx. 7.9 million yen) for the standard model and $250,000 (approx. 39.5 million yen) for the flying race version
The stock price movement was as follows.
-
In pre-market trading, it was up 5% at one point
-
Even after trading began, it was up about 2% at one point
-
The closing price was $354.72. This is a 2.13% drop from the previous day’s $362.44
The trading volume for the day was approximately 62.12 million shares. Since the average for the previous five days was approximately 27.06 million shares, it was a day where 2.3 times the usual number of shares were traded.
There is one more figure that is easy to overlook. Tesla’s stock price had been falling even before the announcement. It fell 5.3% from $382.70 on October 9 to the 15th, the day of the announcement. Including the 16th, it has fallen for five consecutive days.
2. The reason for the decline is “how many units will sell”
Stock prices are determined by expectations of how much a company will earn in the future. They are not determined by whether the video is impressive or not.
Daniel Ives, an analyst familiar with Tesla, says: “Production volume is limited and will not have a significant impact on sales volume or revenue. Investors should not model this as a growth driver.”
Even those who support Tesla see it this way.
The weaknesses reported in the news are all related to sales.
-
Mass production will be in 2028 at the earliest, and flying on public roads requires coordination with the FAA
-
The rear thrusters empty in 6 seconds, and it takes 2 to 6 hours to replenish the air
-
It does not include “FSD,” the autonomous driving technology Tesla is focusing on most
Musk called the Roadster the “last car driven by humans.” In other words, Tesla’s main source of earnings lies in cars that do not require driving. The content of the announcement was not about that core business.
3. Tesla’s announcement events often lead to a decline the next day
This is not the first time.
-
November 2019: Announced the electric pickup “Cybertruck.” The supposedly bulletproof windows shattered during the demonstration, and the stock fell about 6% the next day
-
October 2024: Announced the unmanned taxi “Cybercab.” It was perceived as lacking concrete plans, and the stock fell 8.8% the next day
However, neither event had any relation to the years that followed. The stock price at the end of November 2019, when the Cybertruck was announced, was about $22 adjusted for stock splits. It is now $354.72, an increase of about 16 times. The price at the end of October 2024 for the Cybercab was $249.85, and it is now about 1.4 times that.
What the next day’s price movement tells you is only whether the expectations for that day were too high. It does not tell you the future of the company.
4. How much did the value change for those holding investment trusts?
This is the main point of the Profit and Loss Glasses.
Even if you don’t hold Tesla stock directly, if you hold S&P 500 or All Country investment trusts, Tesla is included in them. I checked the Tesla ratio in the monthly reports of each fund as of the end of September.
-
S&P 500 (eMAXIS Slim US Equity): 1.5%
-
Total US Stock (SBI V Total US Stock): 1.37%
-
NASDAQ 100 (iFreeNEXT): 2.76%
-
All Country (eMAXIS Slim All Country): Not in the top 10 holdings. In the US ETF “ACWI” which tracks the same index as All Country, it is 1.01% (as of October 15)
Assuming you held 1 million yen each, I calculated how much Tesla’s 2.13% drop reduced that person’s assets.
This does not include currency fluctuations or the price movements of other stocks.
For someone holding 1 million yen in the S&P 500, it is about 320 yen. Even for the NASDAQ 100, which has the largest impact, it is about 590 yen.
Even for an announcement that became a global topic, the impact on the wallet of someone holding an index is not even enough to cover the cost of one lunch.
Whether or not you can avoid panicking every time there is news depends not only on the composition ratio, but also on which account you hold the investment trust in.
A general securities account and a NISA account are different things. It is actually common to open only a general account and not apply for NISA. This happens when you thought you were investing through NISA, but were actually buying in a taxable account. You should just check your brokerage’s personal page to see if your NISA account is “opened”.
Furthermore, if you do not yet have a securities account, now is the most advantageous time to open one.
The amount you can receive if you open a securities account now as a Rakuten Mobile user (as of September 23, 2026; source is in the figure).
However, this only applies to Rakuten Mobile users. You can check if you are eligible from the mobile side.
*Referral link by a Rakuten employee (#PR). You can decide after logging in and reading the explanation. Please check the official Rakuten Securities page for the targets and conditions of the securities campaign.
Profit and Loss Judgment
The day after the flying Tesla announcement, Tesla stock fell 2.13%. For someone holding 1 million yen in the S&P 500, this is a matter of about 320 yen, and about 590 yen for the NASDAQ 100.
When viewed through the Profit and Loss Glasses, a spectacular announcement and a profitable announcement are two different things. What the stock price is looking at is not the impact of the visuals, but how many units are sold and how much profit can be made.
The loss comes from deciding to buy individual stocks the next morning while still excited from the presentation. Both of the past two Tesla presentations saw the stock price fall the following day. Conversely, there is almost no need for someone holding an index to think about buying or selling based on this news.
Today’s Profitable Move
-
Take a look at the top 10 holdings in your investment trust’s monthly report once. If you know what percentage of your assets the company in the news accounts for, you can avoid panicking every time there is news.
-
If you want to buy individual stocks after a presentation, wait until you see the closing price the next day to decide. In Tesla’s latest announcement, the stock moved 7 points in one day, from a 5% gain before the market opened to a 2% loss at the close.
-
The numbers to look at are not the video, but the production start date and volume. The Roadster is scheduled to start production in 2028, and the volume has not been released yet.
Now then.
What percentage of your investment trust was Tesla?
*The amounts are rough estimates (approximations) using the Profit/Loss Glasses. The price movement of the investment trust is calculated simply by multiplying the Tesla ratio by the stock price decline rate, and does not include currency fluctuations or the price movements of other stocks. Ratios are as of September 30, 2026 (ACWI is as of October 15), and stock prices are the closing prices on October 16, 2026. This does not recommend buying or selling any specific stock.
*The links to buttons in the text are referral links from Rakuten Group employees (#PR).
*The Rakuten Securities account opening campaign shown in the chart (2,000 points for a general account + 1,000 points for simultaneous NISA account opening, up to 3,000 points) is for users of services such as Rakuten Mobile’s “Rakuten Saikyo Plan,” and requires multiple conditions such as answering a quiz and applying via the campaign page. The account application period is from 10:00 on September 1, 2026, to 9:59 on November 2, 2026, and the points will be awarded as Rakuten Securities points (exchangeable 1:1 for Rakuten Points) around the end of December 2026. The content was confirmed on the Rakuten Securities campaign page as of October 18, 2026. Since conditions and periods are subject to change, please be sure to check the official page.
Sources: Announcement details, off-market trading and price movements during trading, reservation deposits, and Mr. Ives’ remarks = Nihon Keizai Shimbun (October 17, 2026) / Stock prices and trading volume = stockanalysis.com (TSLA daily/monthly) / Decline the day after the Cybertruck announcement = CNBC (November 22, 2019) / Decline the day after the Cybercab announcement = Barchart (October 11, 2024) / Tesla inclusion ratios = Mitsubishi UFJ Asset Management “eMAXIS Slim US Equity (S&P500)” and “eMAXIS Slim Worldwide Equity (All Country)” monthly reports, SBI Asset Management “SBI/V/Total Stock Market Index Fund” monthly report, Amova Asset Management NASDAQ100 Fund monthly report (all as of September 30, 2026), and iShares MSCI ACWI ETF holdings (stockanalysis.com, as of October 15, 2026)
I’ve also looked at smartphone costs using the same glasses.