How Top Buy-Side Investors Analyze Companies in the AI Age

What elite analysts actually do — in their own words and work products — and how AI is changing it

Prepared 8 June 2026 · Built from primary sources: real pitch decks, fund letters, published models and named-practitioner accounts · All links fetch-verified

1. Executive Summary

2. How Top Buy-Side Analysts Actually Work

2.1 The process, from idea to position

Across firsthand accounts, the institutional process runs: idea sourcing (screens, sector coverage, network) → business analysis and a driver-based model → deep dive on the 2–4 factors that actually move the stock → bull/base/bear case construction with risk/reward asymmetry → pitch to the PM → monitoring against catalysts. James Valentine — whose Best Practices for Equity Research Analysts the CFA Institute adopted into its curriculum — frames the core skill as identifying the critical factors per stock and building information networks that give proprietary insight on exactly those (free sample chapter).

Paul Enright, who ran consumer and tech books at Viking Global for 12 years, gives the best single public account of the elite seat in his "Buy Side Primer" (Invest Like the Best, transcript): he separates "great researcher" from "great stock picker," describes what good versus great digging looks like (primary research that tests the thesis, not confirms it), and stresses that business analysis is not stock picking — the stock call is a separate judgment about expectations and timing.

2.2 Models: driver-based, deliberately simple

Practitioner threads and accounts converge on the same philosophy. From a top-voted long/short analyst on WSO:

"You are not trying to out-model the CFO… assume guidance embeds the base case, then find key points that have changed since guidance… The goal is to take a reasonable over/under. It's about taking a view on the company, not the model."

In another thread, the consensus: public-side models are far less granular than PE models because the data doesn't exist — and the edge only requires a different view on one assumption the market has wrong (e.g., net retention of 115% vs. street's 110%). Even a PE principal concedes "the idea that 'the model' helps you make good investments… is a fallacy."

To see what real buy-side-grade models look like, study published ones: Abdullah Al-Rezwan (MBI Deep Dives, ex-buy-side) publishes full deep dives with KPI-driver operating models — see his free Autodesk and Otis deep dives — and his research process post describes the actual sequence: read the filings → build the model shell → write a question list → calls with IR and bulls/bears → write to think. Alta Fox Capital publishes its actual investment decks (XPEL, REVG, Enlabs…) plus the "Makings of a MultiBagger" study it uses as a sourcing framework.

2.3 Single managers vs. pod shops

The depth of work depends on the seat. Single managers (Viking, Maverick, Greenlight lineage) underwrite multi-quarter intrinsic-value gaps with deep primary research. Lee Ainslie (Graham & Doddsville interview) says "the most critical factor we're trying to evaluate is the quality of management," and explicitly warns against valuation-only investing. Larry Robbins (G&D interview) describes Glenview's edge as exhaustive, consistent coverage of a defined universe — "consistency of effort wins the game." At multi-managers (Millennium: 330+ pods, ~$79bn; Point72: 185+ teams), the game is getting quarters right: quarterly projections, beat/miss handicapping, catalyst-linked positioning inside tight risk limits (M&I on multi-managers). Pod analysts re-underwrite assumptions intra-quarter; the model doubles as a sentiment and positioning tool.

2.4 Valuation in practice

Multiples as shorthand: the working valuation in most pitches is earnings power 1–3 years out times a defended multiple range under bull/base/bear scenarios — visible in the real decks in Section 6 (Greenlight's Sohn pitches, Alta Fox's decks, Kerrisdale's short reports all follow this pattern).

Reverse DCF / expectations reading: start from today's price and solve for what it implies. Speedwell Research's explainer shows their actual Meta (Jan 2023) reverse DCF — the market was pricing Meta as if growth was over. The formalized discipline is Rappaport & Mauboussin's Expectations Investing (free tutorials): read price-implied expectations, judge revision likelihood with competitive analysis, express it in probability-weighted scenarios anchored on base rates.

Asymmetry as the filter: PMs look for "60/40 and 70/30 coins," not 50/50 bets (Fundamental Edge), with ~3:1 upside/downside commonly cited as the conviction bar. Position sizing follows fractional-Kelly logic — Thorp's Understanding the Kelly Criterion (PDF) is the primary source — but at small fractions: full Kelly carries ~1-in-3 odds of a 50% drawdown.

3. In Their Own Words: Named Practitioners on Process

The fastest way to absorb elite practice is reading analysts and PMs describing it directly. The highest-signal primary accounts found:

WhoKey process insightSource
Paul Enright (Viking Global, 12 yrs)"Buy Side Primer": researcher vs. stock picker; what great digging looks like; building blocks of an effective pitchILTB transcript
Lee Ainslie (Maverick)Management quality as the central evaluation; longs ~2x shorts; sector heads own deep verticals; valuation alone is not a thesisG&D interview
Larry Robbins (Glenview)Exhaustive consistent coverage of a defined universe; modeling FCF deployment; consistency over flashes of insightG&D interview
Dan Sundheim (D1; ex-Viking CIO)Reading-first routine; qualitative judgment over model precision; risk/shorting process post-GameStopCheeky Pint interview
Li Lu (Himalaya)Research as investigative journalism — physically verifying assets — vs. the "95% of investors" forecasting quarters behind terminals2006 Columbia lecture (PDF)
Mohnish PabraiChecklist built from autopsies of other investors' documented mistakes; cloning as deliberate sourcingG&D interview
François Rochon (Giverny)Annual "owner's earnings" scorecard tracking intrinsic value vs. price; public "Mistakes du jour" error audit in every letterLetters archive
John Huber (Saber Capital)Time-horizon arbitrage as the only durable edge; reading and journaling over screeningLetters & notes
Howard Marks (Oaktree)"Something of Value" (2021): a top practitioner publicly revising his own valuation framework — qualitative depth can justify holding without precise quantificationMemo (PDF)

Deeper archives: the Graham & Doddsville newsletter (Columbia; every issue since 2006 — interviews with Greenblatt, Ainslie, Robbins, Li Lu and dozens of Tiger-descended PMs asked specifically about sourcing, modeling and diligence; latest issue PDF); Value Investor Insight interviews, which force managers through one idea end-to-end (e.g., Rochon, Turtle Creek); and the canonical books of practitioner interviews: Pedersen's Efficiently Inefficient (verbatim process interviews with Ainslie, Asness, Paulson, Chanos), Schwager's Hedge Fund Market Wizards, and Freeman-Shor's The Art of Execution — an allocator's audit of 45 top managers' actual trades showing execution behavior, not idea quality, separated winners.

4. Analytical Frameworks Behind the Process

The named disciplines that recur in elite practice, each with its primary document:

5. The AI-Era Workflow (2024–2026)

5.1 Inside the top funds

FundWhat they've deployedSource
Citadel"Citadel AI Assistant" used daily by nearly all equities investors — scans transcripts/filings, summarizes broker research, flags risks. PMs barred from offloading judgment. Griffin: GenAI "just falls short" for alpha.Reuters · Bloomberg
BalyasnyInternal platform used by ~95% of ~180 teams; agents cut macro scenario analysis from 2 days to ~30 min; proprietary finance-tuned embeddings beat OpenAI's in internal tests.OpenAI case study · Hedgeweek
Viking Global"VikingGPT 2.0" fields ~3 queries/min, usage +400% YoY; deputy CIO uses it as a "sceptical avatar" to stress-test theses. No investment calls.Bloomberg
BridgewaterAIA Labs $2bn fund (July 2024): ML as primary decision basis, humans on risk/execution — "unique alpha uncorrelated to what our humans do."Bloomberg
Man Group"AlphaGPT" generates, codes and backtests signals — several dozen AI-originated signals live (July 2025), human-vetted.Bloomberg
AQRML now drives ~one-fifth of signals in the flagship multi-strategy fund; Asness "surrendered to the machines."Bloomberg
NBIMUses Claude to screen every company entering the portfolio on day one for ESG/ethical risks.CNBC

Adoption data: 95% of hedge fund managers use GenAI (AIMA 2025); 55% of asset managers have AI in at least one investment process but only ~5% grant it any decision authority (Mercer 2026); alternative-data adoption hit ~90% of advisers, led by card-transaction data (Lowenstein Sandler 2025 (PDF)). The strategic divide: Griffin and Asness say efficiency-not-alpha; Bridgewater and Man Group live-trade AI-originated decisions. The market overwhelmingly sits with Griffin for now.

5.2 Working analysts' actual AI workflows

More useful than fund PR: named practitioners publishing exactly how they use LLMs day to day.

Labor-market read from the WSO hedge fund forum: "what used to take 2 analysts can now be done by 1"; expect more top-heavy teams as AI absorbs the modeling grunt work junior seats were built on; lean single managers use AI for breadth ("cover more sectors, peer into foreign markets") rather than cuts. Notably, no major fund's investor letter yet describes its internal AI process in primary terms — funds discuss AI as a position, not a process.

6. Library of Real Work Products (All Links Verified)

Actual artifacts by top investors — the best study material there is. Every link below was fetched and confirmed live on 8 June 2026.

6.1 Pitch decks and research reports

ArtifactWhat it isLink
Greenlight — Sohn 2026 deckEinhorn's actual conference pitch, from Greenlight's own site (2025 and 2024 decks also posted there)PDF
Einhorn — Lehman short speech (2008)"Accounting Ingenuity" — the famous Sohn speech, from Yale's FCIC archivePDF
Pershing Square — Herbalife deck"Who Wants to Be a Millionaire?" — the ~334-slide short thesis (Dec 2012)PDF (archive.org)
Pershing Square — 2026 annual presentationPosition-by-position theses on the current portfolio, published by the fundPDF
Starboard — Darden deck (2014)The ~294-slide "Olive Garden" activist plan — the genre's most famous deckPDF
Kerrisdale — CoreWeave short (2025)Full short thesis with model assumptions; Kerrisdale publishes all reports freePDF
Muddy Waters — Sportradar (2026)Forensic short report; full archive on their sitePDF
Hindenburg — Adani / NikolaFull forensic reports, still liveAdani · Nikola
Sohn Idea Contest archive~20 winning pitch decks 2016–2021, direct PDFsArchive
Alta Fox — research libraryA fund publishing its actual investment decks + the "Makings of a MultiBagger" sourcing studyLibrary

6.2 Fund letters (process in the wild)

ArchiveWhat it isLink
Nomad Partnership letters 2001–14Sleep & Zakaria's complete letters — the modern classic on long-horizon process; authorized copy from Sleep's own foundationPDF
Buffett Partnership letters 1957–70The original — position categories (generals/workouts/controls), sizing logic, expectations-settingPDF
Howard Marks — complete memos 1990–presentFull archive plus a single compiled PDF on Oaktree's siteArchive
Third Point quarterly lettersLoeb's letters — thesis summaries per position (Q2 2025 verified)PDF
Michael Burry — Scion lettersCompilation of Scion's 2000s annual lettersPDF
Giverny Capital letters 1993–presentRochon's owner's-earnings scorecard and "Mistakes du jour" every yearArchive
Ongoing letter aggregatorCurated quarterly collection across hundreds of fundsFinMasters

6.3 Published analyst research and models

SourceWhat it isLink
MBI Deep DivesEx-buy-side analyst's full deep dives with operating models; Autodesk and Otis dives are free PDFs; model library subscriber-gatedADSK dive · Models
Speedwell ResearchIndependent shop publishing institutional-length reports (50–170 pp); frameworks and reverse-DCF explainers free, full reports paidSite
ValueInvestorsClubArchive of member-written long/short write-ups by practicing professionals; free delayed guest accessVIC
Graham & Doddsville archiveEvery issue since 2006 — the richest free archive of fund analysts describing process verbatimArchive
Damodaran spreadsheetsThe one non-practitioner source worth keeping: full valuation model library (ginzu DCF, sector models), free, no signupSpreadsheets

7. A Suggested Modern Workflow

Synthesizing the firsthand accounts into a sequence — the elite process with the AI layer where practitioners actually put it:

8. Source Notes & Caveats