Negative and Exclusionary Screening

Cutting bad stocks out.

How investors screen out harmful sectors and scandals from portfolios.

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Introduction to Negative and Exclusionary Screening 

Negative screening is about knowing where not to invest. 

Before analyzing balance sheets or forecasting returns, many investors first remove companies involved in harmful sectors or serious misconduct. 

These exclusions are based on clear rules—like banning coal producers, limiting exposure to controversial weapons, or dropping firms involved in major scandals. 

This lesson breaks down the five core tools investors use to build portfolios that reflect their values from the start.

Sector & Product Bans

Sector and product bans are the most direct filter. 

Investors define activities—thermal‑coal mining, oil‑sands refining, tobacco production, civilian firearms, cluster munitions, gambling, adult entertainment—that are never tolerated. 

Every security issued by a firm engaged in the banned line is excluded regardless of revenue share, momentum, or governance pedigree. 

The clarity simplifies compliance, audits, and client communication while sidelining high legal and stranded‑asset risk.

Alex’s Sector Exclusion List

Alex applies a sector ban. He exports a global fund’s holdings into Excel and tags each issuer with industry codes from his data vendor. 

Any pure‑play coal miner, tobacco maker, or handgun seller is deleted. 

Forty‑two names—5 % of total weight—vanish, trimming exposure to Australian resources and U.S. staples. 

Alex names the sheet “Red List” and scripts a cross‑check that blocks future trades in those tickers, locking the policy into daily workflow.

Norm‑Based Screens

 Norm‑based screens judge conduct, not products. 

Data providers scan lawsuits, NGO findings, sanctions, and media for breaches of the UN Global Compact, OECD Guidelines, ILO labour rights, or Paris climate targets. 

A confirmed breach moves the company onto an exclusion roster until credible remediation is independently verified. 

The rule protects portfolios from reputational shocks and aligns capital with globally accepted baseline standards of human and environmental behavior.

Revenue Limits

Revenue thresholds add nuance where blanket bans feel too blunt. Investors allow de‑minimis involvement—often below 5 % of sales—while excluding firms materially dependent on the flagged activity. 

Common caps: 5 % for thermal coal, 10 % for military weapons, or 15 % for animal testing. 

Analysts pull segment data from filings; if a company breaches the ceiling it is ineligible until divestiture lowers exposure below the line for two successive reports.

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