FTB-C000627 / Formula component

Log-Price Trendline

Log-Price Trendline is a straight line fitted to the natural logarithm of positive pivot prices.

Intermediate Formula defined 1 linked topicEvidence-reviewed

Definitions

In plain terms

Equal vertical distance in log price represents a ratio-like difference in the original price scale.

Technical

z_i=log(p_i) and the model is z_hat_i = a + b t_i for positive finite prices.

Scope

A log-space line is not interchangeable with an arithmetic-price line.

Formula

z_hat_i = a + b t_i where z_i = log(p_i)
LaTeX: z_i=\log p_i,\quad \widehat z_i=a+bt_i
SymbolMeaningUnit
p_ipositive pivot priceprice

Output unit: log-price

Examples

  • A reviewer computes Log-Price Trendline on a small deterministic fixture and checks timing, units, and boundary behavior before publication.

Common misconceptions

  • A log-space line is not interchangeable with an arithmetic-price line.

Concept relationships

Prerequisites

Related

Required by

Where this concept is used

Tutorials planned

These catalogued topics use this concept, but their complete build has not shipped yet.

  • D08-F01-A04 Important

Evidence and governance

  1. numpy.log NumPy · first party technical publication

    Supports: preferred label, short definition, technical definition, formula

    Limits: A log transform requires positive finite prices and does not by itself define a financial level.

  2. sklearn.linear_model.RANSACRegressor scikit-learn · first party technical publication

    Supports: preferred label, short definition, technical definition, formula

    Limits: This package enumerates every two-point hypothesis for small pivot sets instead of using random sampling.

  3. Linear Least Squares Regression NIST/SEMATECH · official standard

    Supports: preferred label, short definition, technical definition, formula

    Limits: A fitted line remains descriptive and is not evidence of a future price path.

  4. numpy.polyfit NumPy · first party technical publication

    Supports: preferred label, short definition, technical definition, formula

    Limits: The glossary freezes its own log-space OLS contract, diagnostics, and tie rules.

Reviewed by
fintech-builder-batch-011
Last reviewed
2026-08-09
Next review
2027-08-09
Record status
evidence reviewed

This record is evidence-reviewed and readable, but not yet promoted to published — it is served noindex,follow and excluded from the sitemap.

Written by

Fintech engineer building market-data and financial systems, and the author of every article, glossary record, and reference implementation on The Fintech Builder.