Signal stacking layers multiple data signals together to achieve higher confidence in a target account's readiness to buy. One signal is weak. Five converging signals is a strong buy indicator.
One firmographic anchor + one technographic qualifier + one behavioral trigger = highest-confidence stack.
Example: SaaS company (50–500 employees) + uses Salesforce + hired 3+ SDRs in last 30 days = company actively building outbound = high relevance for a sales automation platform.
Define suppression signals: competitor to your company, headcount under 10, government/non-profit (if not your segment), recently acquired (decisions paused).