Investing– category –
Independent explanations of investment mathematics, funds, valuation and technology, with transparent calculations and primary sources. Choose a starting point below.
Getting started: A practical first-month investing plan · Investing small amounts and managing fees
Understanding returns and risk: CAGR versus average returns · Leverage, margin and daily reset
Technology and market flows: AI data centers and electricity demand · Memory stock buybacks and index flows
Memory companies and AI economics: HBM, DRAM and NAND company map · Five tests for a memory supercycle · AI capex, depreciation and cash flow
Decisions when stocks disappoint: Why good earnings can send a stock lower · The break-even trap before averaging down
Check the assumptions behind each example. Product availability and tax treatment depend on your country and account.
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ETFs vs Mutual Funds: Exposure, Trading and the Costs That Matter
Compare ETF and mutual-fund trading, NAV, fees and automation, with an original bid–ask spread example. -
Growth vs Value Stocks: Expectations, Price and the Risk of Simple Labels
English · 日本語 Growth and value are useful descriptions, but neither is a permanent winner. A fast-growing business can disappoint its shareholders if the ... -
Survivorship Bias in Investing: The Winners You See and the Losses You Miss
English · 日本語 An investor who became wealthy has an interesting story. That story is not a complete dataset. People who lost money, closed accounts or sto... -
Portfolio Backtesting: A Beautiful Chart Is Not a Forecast
English · 日本語 A portfolio backtest asks what a specified rule would have produced under a particular historical dataset. It does not tell you what the sam... -
QYLD and XYLD: Distribution Yield Is Not Total Return
English · 日本語 A large monthly distribution is easy to notice. A changing investment value is easier to overlook. Covered-call ETFs can produce regular cas... -
Diversification Explained: Count Risks, Not Just Funds
English · 日本語 Owning many investments is not the same as spreading your risks. Three technology funds can hold similar companies, depend on the same valua... -
Personal Inflation: Why Your Cost of Living Can Rise Faster Than CPI
English · 日本語 A national inflation figure describes a broad average. Your grocery bill, rent and electricity costs describe a particular household. Both c... -
The Semiconductor Supercycle: AI Growth, Memory Prices and Valuation Risk
English · 日本語 AI can create durable growth in demand for computing while semiconductor businesses still experience cycles. These statements are compatible... 広告
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The Buffett Indicator: A Valuation Lens, Not a Market Timer
English · 日本語 The Buffett indicator compares stock-market capitalization with gross domestic product. It is widely discussed as a broad valuation signal, ... -
CAGR vs Average Returns: Why Gains and Losses Do Not Cancel
English · 日本語 An investment that gains 50% and then loses 50% has not broken even. A starting value of 100 becomes 150, then 75. The average of the two an... -
Dollar-Cost Averaging: A Lower Average Cost Is Not a Guaranteed Profit
English · 日本語 Dollar-cost averaging means investing equal amounts at regular intervals. It buys more units when prices are low and fewer when prices are h... -
VT, VTI and VOO: When More ETFs Mean More Overlap
English · 日本語 Owning three ETFs does not necessarily give you three independent sources of diversification. A global stock fund, a US total-market fund an...
