How did 'equity' semantically shift to signify 'Assets — Liabilities'?

[scherz0]

Here I ask merely ask about Equity = Assets — Liabilities here, not its meaning as stock. 1. Why was 'equity' was adopted to describe this difference?

equity

: In the real-estate world, this term refers to the difference between the market value of your home and what you owe on it. For example, if your home is worth $400,000, and you have an outstanding mortgage of $150,000, your equity is $250,000. Equity is also a synonym for stock.

2. What semantic notions underlie 'Assets — Liabilities' with the original Latinate meanings of equity beneath, like the emboldened abstract nouns that I emboldened?

early 14c., "quality of being equal or fair, impartiality in dealing with others," from Old French equite (13c.),
from Latin aequitatem (nominative aequitas) "equality, uniformity, conformity, symmetry; fairness, equal rights; kindness, moderation,"
from aequus "even, just, equal" (see equal (adj.)).
As the name of a system of law, 1590s, from Roman naturalis aequitas, the general principles of justice which corrected or supplemented the legal codes.