The weekly quiz

Answer: The stock had more than doubled this year and was trading above the average analyst price target, so it was priced for perfect. When a stock is priced for perfect, good isn't good enough. Fortinet had run up so much going into the report that any soft spot got punished. Watch that part of “Fortinet Stock Crashed After Beating Earnings. Overreaction? (FTNT)” (2:34)

Answer: The S&P 500 sizes each company by its total stock market value, so bigger companies get more of your money. Nobody at Vanguard went all in on AI. The index weights companies by market value, so as Nvidia's stock grew, its slice grew on its own, and every new dollar you add buys a little more of it. Watch that part of “VOO Is 21% Nvidia, Apple and Microsoft. Is It Secretly an AI Bet?” (0:36)

Answer: Old sites and videos may still show the $2,200 target next to the new $144 price, which makes the upside look huge when it really means $275. After the split, you divide old targets by 8, so Cantor's $2,200 really means $275. If you put $2,200 next to a $144 stock, it looks like more than 1400% upside, but it's the same pizza. Watch that part of “Sandisk Stock Split: The Price-Target Trap to Avoid” (1:44)

Answer: Up more than 40%. Revenue was $13.4B, +44.7% from $9.25B a year earlier. AMD's earnings, quarter by quarter

Answer: Above the top of its own range. Revenue came in at $2.18B, against its own forecast of $2.06B to $2.08B. That forecast is the company's own number, not Wall Street's. APP's earnings, quarter by quarter

Answer: It mixes in older targets, like the highest one set back in February, while the five set since late July average about $10.60. The newest targets are way lower than the average. The highest one was set back in February when the stock was much higher, which is like checking February's forecast to decide if you need a jacket today. Watch that part of “Wall Street Says This $2 AI Power Stock Is Worth $16. I Checked Who Said It. (FRMI) (Fermi Stock)” (3:45)

Answer: About $77,000. Early on, you're doing most of the lifting yourself. In the model, about $77,000 is your own contributions and growth only adds about $23,000, which is why it can feel like nothing is happening. Watch that part of “Why Everything Changes After Your First $100K Invested” (1:01)

Answer: People trading Brazilian stock index futures who kept going for at least 300 days and lost money. It comes from a study of people who started trading Brazilian stock index futures in 2013 through 2015. It's not about all traders or ordinary US stock trading, and it's not a 97% chance you lose everything. Watch that part of “Is Day Trading Worth It? I Did the Math on the Hourly Pay” (6:59)

Answer: Up more than 40%. Revenue was $1.39B, +44% from $962M a year earlier. SOFI's earnings, quarter by quarter

Answer: Yes, a profit. Its GAAP earnings per share were $0.59. SBUX's earnings, quarter by quarter

Answer: Because the 29% describes June's backlog, not October's awards. That 29% was a June number for a different set of contracts. If you apply it to the October awards, you're quoting a number the company never actually disclosed. Watch that part of “This $2 AI Stock Just Announced $225 Million in Contracts. Read the Footnote. (BBAI Stock)” (2:59)

Answer: It includes options that haven't been exercised and contract ceilings, and doesn't necessarily reflect funded amounts. Total contract value is basically the biggest number the awards could ever add up to. Some of it may never turn into work, so you shouldn't treat it like money already earned. Watch that part of “This $2 AI Stock Just Announced $225 Million in Contracts. Read the Footnote. (BBAI Stock)” (2:00)

Answer: Ask Sage, the generative AI business it acquired. The company tied the increase to Ask Sage, a business it bought. That's why you want to separate growth a company bought from growth in the business it already owned. Watch that part of “This $2 AI Stock Just Announced $225 Million in Contracts. Read the Footnote. (BBAI Stock)” (3:38)

Answer: Yes, a profit. Its GAAP earnings per share were $0.22. TSLA's earnings, quarter by quarter

Answer: Up more than 40%. Revenue was $14.6B, +161.4% from $5.58B a year earlier. SPCX's earnings, quarter by quarter

Answer: Avoid becoming a forced seller when the market falls. The lesson isn't to sit on cash forever. You keep emergency savings separate and stay careful with margin so you're never forced to sell at the worst time. Watch that part of “Stop Copying Buffett’s Stocks. Copy His Strategy.” (1:17)

Answer: To the existing shareholders who are selling, not to the company. Primary shares are sold by the company, so that cash can grow the business. Secondary shares are sold by existing owners, so that cash goes to them instead of the company. Watch that part of “Don't Buy the Next Big IPO Until You Check These 7 Things” (1:46)

Answer: Compare buying a new stock with other options, like adding to your best understood holding, paying down expensive debt, an index fund or holding cash. Just like Greg Abel decides where Berkshire's next dollar earns the best risk-adjusted return, you weigh each new dollar against its alternatives. Don't buy something just because the ticker is popular. Watch that part of “Stop Copying Buffett’s Stocks. Copy His Strategy.” (3:18)

Answer: Roth IRA. Roth IRA. The catch: The $7,500 limit is shared across all your IRAs, so traditional and Roth IRA contributions together can't go over it for 2026. Read “Roth IRA” in the glossary

Answer: Tax-loss harvesting. Tax-loss harvesting. The catch: Harvesting a loss lowers your cost basis on whatever you reinvest in, so in many cases it pushes the tax down the road rather than making it disappear. Read “Tax-loss harvesting” in the glossary