About the author
Nikolaos Drongitis
Founder & Head of Investment Research
Nikolaos Drongitis founded Ploutos AI, an investment research tool that uses artificial intelligence to analyse US-listed companies, and is responsible for the research it publishes.
He designed the Ploutos methodology and built the system that turns companies' official SEC filings into structured financial analysis. The analyses cite the filings their figures come from, and where the data runs out they say so instead of guessing.
On the blog he writes about fundamental analysis, stock valuation, ETFs and the methodology behind Ploutos AI, explaining both what the data shows and where the analysis stops.
- Articles
- 24
- Topics
- 4
- Latest article
- Oct 4, 2026
How he writes
The principles behind the research and the articles of Ploutos AI.
Primary sources
The analysis rests on companies' official SEC filings, cited so the reader can check the data.
Open about the limits
Where the data falls short, he says so plainly. Uncertainty is not papered over with guesses.
Understanding, not recommendations
He explains what the financials show and how to read them. He never tells anyone what to buy or sell.
Topics
The topics covered on the blog, with how many articles in each.
- Fundamental analysis11How to read a company from its numbers: revenue, earnings, cash flow and competitive advantage.
- Valuation4When a price is expensive or cheap for the business behind it, and how far to trust an estimate.
- ETFs4What a fund actually holds, and how much two funds overlap.
- How Ploutos works5Our method, our sources, its limits, and how we keep score on ourselves.
How different are the most popular ETFs? We measured 35 pairs
SPY, VOO and IVV share 99.6% or more. VTI is 88% S&P 500. Two dividend funds, SCHD and VYM, share only 21.4%. The overlap of 35 popular ETF pairs, from their SEC filings.
Nikolaos DrongitisRead the article 
Bond ETFs: yield to maturity, duration and credit risk, simply
How to read a bond ETF: what yield to maturity means, how duration shows how far the price falls when rates rise, and why more yield means more risk.
Nikolaos DrongitisRead the article 
Dividend yield and payout ratio: when a dividend is at risk
Why a high dividend yield does not mean a safe dividend: how yield is calculated, what the payout ratio shows, why cash flow coverage matters, and the signs that usually come before a cut.
Nikolaos DrongitisRead the article 
How to read a 10-K: a US company's annual report, without getting lost
What a 10-K is, where to find it, which parts to read first and what to look for in each. A guide to the annual filing US companies make with the SEC.
Nikolaos DrongitisRead the article 
Insider trading and Form 4: what it means when an executive buys or sells their company's stock
What Form 4 is, who counts as an insider, how to tell a real purchase from stock pay, and why an executive's sale usually says less than a purchase.
Nikolaos DrongitisRead the article 
ROIC and ROE: how well a company puts its money to work
Return on invested capital (ROIC) and return on equity (ROE) explained simply: how they are calculated, why ROE is flattered by debt, and why ROIC says more about the quality of a business.
Nikolaos DrongitisRead the article 
The full analysis
What do a company's filings show?
The guides explain the method. The full Ploutos AI analysis reads everything a company has filed and shows what stands behind its figures, with a source for each one.
- A fair value range built from the filings
- Earnings quality, debt and red flags
- Insider and institutional moves
- The case for and the case against