Investing guides, with S&P 500 data
13 guides that explain the concepts this site works with, using figures measured on the S&P 500 and links to their sources. They are educational: not investment recommendations, and they take no one's circumstances into account.
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What the S&P 500 is: how it is built, who decides and how you invest in it
What the S&P 500 is, with August 31, 2026 data: 503 constituents and 500 companies, who decides additions and deletions, the official S&P Dow Jones Indices requirements, the sector breakdown, how much the ten largest weigh and how it is bought.
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How to read a Quant500 company page
A guide to reading any S&P 500 company page on Quant500: the 0-to-10 factor scores and how they are computed, the P/E built on SEC earnings, the 10-K, 10-Q and 8-K filings, insider trades and the nine tabs, with Apple as the example.
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S&P 500, Nasdaq-100 or MSCI World: compared
Returns, worst drawdowns, volatility, top-10 weight, overlap and cost of the three indices from official data, and how funds and ETFs are taxed in Spain.
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Equal-weight vs. cap-weighted S&P 500: the data
What changes when all 500 companies weigh the same: the top 10 make up 40%, RSP vs. SPY year by year since 2003 and the history since 1998.
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Sharpe ratio, max drawdown and CAGR: the basics
What CAGR, volatility, maximum drawdown and the Sharpe, Sortino and Calmar ratios measure, with the numbers of a simulated S&P 500 portfolio.
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10-K, 10-Q and 8-K: SEC filings explained
The 10-K is the audited annual report, the 10-Q the quarterly one and the 8-K the notice of material events: what each contains and when it arrives.
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Value investing: what it is and its track record
A 20-stock S&P 500 value portfolio would have returned 11.36% a year in 1998-2026 (simulated), with an 80% drawdown. What value investing is.
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P/E ratio explained: compare it with its sector
What the P/E measures, how it differs from the forward P/E and why it must be compared with its sector: medians for the 11 S&P 500 sectors on 9/18/2026.
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$100 a month in the S&P 500: what you'd have
The numbers over 10, 20 and 25 years with specific dates: paid in, final value, the worst moment along the way and how much the starting month changes.
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How US stocks are taxed for residents of Spain
15% withholding with W-8BEN, the Spanish foreign tax credit, 2026 savings brackets, capital gains, losses, the two-month rule and Form 720, with sources.
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Momentum investing: what it is and its S&P 500 record
A 20-stock S&P 500 momentum portfolio would have returned 9.93% a year in 1998-2026, vs 10.37% for equal-weight. What momentum is and how it is measured.
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Investing in the S&P 500: index, equal-weight or factors
Cap-weighted index, equal-weight or factors: what each one is and what it delivered in 1998-2026, with drawdowns, costs and currency. No recommendations.
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Insider buying: what it is and this month's S&P 500 buys
Form 4, code P and pre-planned sales: only 993 of 42,295 insider transactions are purchases with their own money. Plus the September 2026 buys.
To go further: the Academy course, the Methodology behind the rankings and the S&P 500 daily report.
With today's data: the dividend yield of every S&P 500 company, with payout ratios and upcoming ex-dividend dates.
To check the figures yourself: the open data, with the files these guides are built on, their licence, their field dictionary and how to cite them.
Each guide states the cut-off date and source of its figures. Where they quote model portfolio results, those are historical simulations: past performance does not guarantee future returns. Not financial advice.