History of the quick ratio
The acid-test name predates the ratio. The 1.0 threshold has held for a century. Here is the lineage and what changes today.
The term acid-test comes from the 19th-century assayer's nitric acid test for gold purity, used as a metaphor for any rigorous quality check. The acid-test ratio entered US credit analysis vocabulary in the 1920s as commercial bankers sought a stricter version of the current ratio that excluded slow-moving inventory. The 1.0 threshold that anchors most textbook definitions today has been stable since mid-century and survives in the current edition of Subramanyam's Financial Statement Analysis textbook.
Verified June 2026. Source: Subramanyam, Financial Statement Analysis, 11th Edition (2014), Chapter 10 (pp. 499-505).
Lineage
19th century: the assayer's nitric acid test
Gold prospectors and assayers used nitric acid to verify gold purity: gold resists the acid, base metals dissolve. The phrase acid-test entered the English language as a synonym for a rigorous, fast pass-or-fail check.
1920s: US commercial bankers want a stricter ratio
The current ratio (current assets / current liabilities) had been used as a credit yardstick since the late 1800s, but bankers found that inventory-heavy borrowers could pass the current ratio test and still fail to pay on time when stocks proved hard to liquidate. Stripping inventory out of the numerator produced a stricter ratio that better predicted repayment performance. The new ratio borrowed the acid-test metaphor.
Mid-20th century: textbook canonisation
The acid-test ratio appears as a standard credit and liquidity metric in every major financial statement analysis textbook published from the 1960s onward. The 1.0 minimum threshold for general industrial firms became the default rule of thumb.
Late 20th century: industry-adjusted thinking
Penman, White-Sondhi-Fried, and Subramanyam all push back against the flat 1.0 threshold and advocate reading the quick ratio against the cash conversion cycle and industry-specific operating cycles. The Damodaran NYU Stern Working Capital dataset, refreshed annually each January, provides the quantitative anchor for industry-adjusted bands.
2010s onward: SaaS, lease accounting, AR factoring
Three accounting shifts complicate modern quick ratio reading: deferred revenue from subscription businesses inflates current liabilities, ASC 842 brings operating lease liabilities on balance sheet, and AR factoring removes receivables from reported assets. Analysts now routinely make adjustments before comparing across firms.
Why the 1.0 threshold survives
The 1.0 threshold persists because it expresses a useful arithmetic fact: a firm with quick ratio above 1.0 can cover every dollar of current liabilities from near-cash assets without selling inventory or drawing on a revolver. That is a clean binary answer to a clean binary question. The threshold is a rule of thumb, not a regulation, and it is overridden by sector- specific bands for industries (retail, restaurants, telecom) where it has never been a fair test.
Verified June 2026. Source: Penman, Financial Statement Analysis and Security Valuation, 5th Edition (pp. 718-720).
Interpreting the ratio today
Strong, healthy, tight, stressed bands and how industry context overrides them.
Every citation in one place
The textbook anchors, Damodaran dataset, and verification dates.