★ BEST INVESTING TOOLS COMPARISON ★
VOL. XCIV, NO. 247
Tool comparison edition
Tool Comparison
Letters and Reviews vs Portfolio123
Letters and Reviews
Best for institutional ownership
Free
Portfolio123
Best for screeners and data visualizations
Free • From $25/mo
Outbound links may include affiliate or sponsor codes.
The verdict
The bottom line
Letters and Reviews and Portfolio123 cover a lot of the same ground (2 shared categories, stock ideas and blogs), so for the basics you won't go far wrong with either. Portfolio123 simply does more: 19 categories to Letters and Reviews's 3, including screeners, data visualizations, and quant. Letters and Reviews counters by being completely free.
Key differences at a glance
- Real-time data
- Portfolio123
- Broader coverage
- Portfolio12319 vs 3 categories
- Desktop app
- Portfolio123
- API access
- Portfolio123
- Asset coverage
- Portfolio123Adds closed-end funds
- Free plan
- Both
Choose
Letters and Reviews if…
- You care about institutional ownership, something Portfolio123 doesn't offer
Choose
Portfolio123 if…
- Delayed quotes won't cut it; you need real-time data
- You want an API so you can script or automate things
- You care about screeners, data visualizations, and quant, things Letters and Reviews doesn't offer
Comparison snapshot
| Attribute | | |
|---|---|---|
| Pricing & plans | ||
Starting price | Free | Free • From $25/mo |
Free tier | Yes | Yes |
Free trial | — | — |
Plan limits | — | Free Screener & Backtesting Access: duration days: 30 |
| Platforms & access | ||
Web app | Yes | Yes |
Desktop app | No | Yes |
Mobile app | No | No |
API access | No | Yes |
Broker sync | — | Yes |
Integrations | — | Interactive Brokers and Tradier |
| Audience & fit | ||
Experience level | Beginner, Intermediate, Advanced | Beginner, Intermediate, Advanced |
Best for | — | Retail Traders, Pro Retail +5 more |
Categories covered | 3 | 19 |
Regions | North America, Europe, APAC | North America, Europe |
| Data & capabilities | ||
Data quality | — | 5 signals: Latency: Real-time and End of Day, Granularity: EOD +3 more |
Data partners | — | 4 partners: FactSet, S&P Global Market Intelligence +2 more |
Capabilities | — | 6 signals: Custom formulas, Ranking backtests +4 more |
| Try it | Visit Letters and Reviews | Visit Portfolio123 |
Standout features
What Letters and Reviews does best
- Quarterly **Fund Manager Letters** pages with the fund name, date, and a "Stocks Mentioned" column (tickers link out for quick lookup); latest public quarter observed is Q4 2025.
- Quarterly **13-F pages** the author reads, with many entries including holdings tables and position-change flags (e.g., NEW / Sold Out / % of portfolio).
- Lightweight **About** page clarifies the goal: stock-idea discovery from letters; author shares links and invites tips via @_iinvested.
- A small **Podcasts** page curating investing/finance episodes the author plans to re-listen to.
What Portfolio123 does best
- Web‑based quant research terminal for building multifactor ranking systems, stock/ETF screens, and complete rules‑based strategies with no programming, powered by point‑in‑time FactSet data and marketed as free of survivorship and look‑ahead bias.
- Supports realistic simulations and backtests over roughly 20 years of history for US, Canadian, and European equities, with custom universes, separate buy/sell rules, position sizing, hedging, and “Book of Strategies” to combine and analyze correlated systems.
- Stock & ETF coverage uses fundamentals, estimates, corporate actions, plus industry/sector classification, with “over 15,000 current US, Canadian, and European stocks” and many more historical issues.
- AI Factor lets users train machine‑learning predictors for expected returns and plug the predictions into ranking systems, strategy simulations and asset-level analysis, with no-code model evaluation, blocked K-fold cross validation, lift charts and model/portfolio statistics.
- Homepage currently advertises 30 days of free screener and backtesting access with no credit card required, in addition to the free Manage module.
Data & access details
| Attribute | | |
|---|---|---|
| Coverage & fit | ||
Asset types | StocksETFs | StocksETFsClosed-End Funds |
Experience | BeginnerIntermediateAdvanced | BeginnerIntermediateAdvanced |
Target audience | Not specified | Retail TradersPro RetailInstitutional InvestorsAnalystsQuants/DevelopersFinancial AdvisorsStudents/Researchers |
Regions | North AmericaEuropeAPAC | North AmericaEurope |
Coverage details | Identifiers: Ticker | Countries: US and CAIdentifiers: Ticker |
| Data | ||
Data freshness | Not specified | Real-timeEnd of Day |
Data granularity | Not specified | EOD |
Data partners | Not specified | FactSetS&P Global Market IntelligenceICE Data ServicesFRED |
| Access & integrations | ||
API protocols | Not specified | REST |
API auth & delivery | Not specified | Auth: APIKeySDKs: PythonDocs |
Import methods | Not specified | BrokerOAuthCSV |
Integrations | Not specified | Interactive BrokersTradier |
Export formats | Not specified | CSVJSON |
| Plans & trust | ||
Capability signals | Not specified | Custom formulasRanking backtestsUniverse builderBroker syncRebalancingCorrelation |
Vendor & support | Letters and Reviews (Blogger)Support: Email | Portfolio123Support: Forum |
Curation ratings | Methodology 3/5Reliability 3/5UX 3/5 | Not specified |
Green tags are exclusive to that tool in this comparison.
Pricing breakdown
Free
Lower starting price
Plans & pricing
$25/mo
Starting price
Plans & pricing
- duration days: 30
Coverage overlap
Shared categories
2Where the two tools cover the same ground.
Letters and Reviews strengths
1What you only get with Letters and Reviews.
Portfolio123 strengths
17Community category leaders
Vote sentiment comparison
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Frequently Asked Questions
What's the difference between Letters and Reviews and Portfolio123?
Letters and Reviews leans toward stock ideas, institutional ownership, and blogs, while Portfolio123 puts more weight on screeners, data visualizations, and quant. They overlap in 2 categories, so for most people it comes down to workflow preference and price.
How much do Letters and Reviews and Portfolio123 cost?
Good news: both Letters and Reviews and Portfolio123 have free plans, so you can run them side by side and only pay if you hit a wall.
Does Letters and Reviews or Portfolio123 have an API?
Portfolio123 has an API for programmatic access and custom integrations. Letters and Reviews doesn't, so you're working through its interface.
Should I choose Letters and Reviews or Portfolio123?
It depends on what you're after. Pick Letters and Reviews if institutional ownership matter to you; go with Portfolio123 if you'd rather have screeners and data visualizations. And if you only need the basics both share, let price decide.
What asset classes do Letters and Reviews and Portfolio123 cover?
Both cover stocks and ETFs. Portfolio123 adds closed-end funds on top.
Does Letters and Reviews or Portfolio123 have real-time data?
Portfolio123 offers real-time data, which matters if you trade actively. Letters and Reviews runs on delayed or end-of-day data, which is perfectly fine for longer-term investors who don't live and die by the tick.
Can I export data from Letters and Reviews and Portfolio123?
Portfolio123 exports to CSV. Letters and Reviews is stingier about getting data out.
Which has a better stock screener: Letters and Reviews or Portfolio123?
Portfolio123 has a stock screener for surfacing ideas; Letters and Reviews doesn't, and focuses its energy elsewhere.
Can I track my portfolio with Letters and Reviews or Portfolio123?
Portfolio123 handles portfolio tracking. Letters and Reviews is really a research tool; you'd track your portfolio elsewhere.
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Curation & Accuracy
This directory blends AI‑assisted discovery with human curation. Entries are reviewed, edited, and organized with the goal of expanding coverage and sharpening quality over time. Your feedback helps steer improvements (because no single human can capture everything all at once).
Details change. Pricing, features, and availability may be incomplete or out of date. Treat listings as a starting point and verify on the provider’s site before making decisions. If you spot an error or a gap, send a quick note and I’ll adjust.