---
title: "Stock Alert Concepts | Pensel"
description: "Learn the key ideas behind percentage-based stock alerts, price baselines, and how they work."
source: "https://pensel.cc/concepts/"
---
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Concepts

# Understand stock alert concepts

Clear explanations of percentage alerts, price baselines, and the ideas that help make stock alerts more useful.

*   [
    
    ## Baseline Percentage Alerts: The Complete Guide
    
    A baseline percentage alert triggers when a stock or ETF moves a set percentage from a baseline - opening price, moving average, or 52-week extreme - instead of a fixed price target.
    
    Read concept →](/concepts/percentage-based-stock-alerts)
*   [
    
    ## It Even Changes Day to Day: The Baseline Recalculates Every Single Time
    
    It's easy to accept that a baseline drifts across seasons. The deeper truth is it never holds still at all - the 30-day average on Sep 13 is already different from Sep 1, twelve days later, same month, same stock.
    
    Read concept →](/concepts/daily-recalculated-baseline)
*   [
    
    ## The Baseline Moves Too: Why a 30-Day Average Can't Be Captured Once
    
    Most percentage alerts quietly freeze their baseline the moment you create them. Pensel recalculates it continuously - so a rule you set in January still means the same thing in September, instead of measuring against a stale number.
    
    Read concept →](/concepts/moving-baseline-explained)