John Moody's 1909 railroad bond ratings became the language of credit

By 1909 American railroads had raised enormous debts from a scattered public of investors, and there was no common way to compare the quality of one bond against another — each buyer waded through statements alone. John Moody had published a statistics manual since 1900, but the Panic of 1907 destroyed his first venture.

His 1909 comeback, 'Moody's Analyses of Railroad Investments', focused solely on railroad bonds and did something new: it assigned each security a symbolic rating. Moody credited rating efforts in Vienna and Berlin for the idea, and borrowed the letter symbols from mercantile credit-reporting firms — but he was the first to publish ratings widely, in an accessible format, funded by investors' subscription fees.

The format spread because it was the cheapest information an investor could buy. Poor's followed in 1916, Standard Statistics in 1922 and Fitch in 1924, all converging on the same letter scheme — by competing, they standardized it. In 1936 the Comptroller of the Currency barred banks from buying 'speculative investment securities' as determined by 'recognized rating manuals', writing Moody's private letters directly into banking law.

That 1936 rule converted a subscription newsletter into infrastructure: from then on, a bond's marketability depended on which letter sat beside it. The scale no longer described the market; it organized it.

An independent letter grade sold to investors, not issuers

One symbol replaced hours of individual analysis, and comparability — not depth — was what investors would pay for.

Subscription funding from investors kept the verdicts independent: the rater had no stake in the rated, so the grade meant something.

Rivals copying the format multiplied its reach; every new agency's ratings made the letter scale more universal, not less.

The 1936 bank regulation turned adoption into obligation — banks legally needed a rating, so the standard could no longer be bypassed.

A scale beats a dossier. Moody compressed bond fundamentals into one comparable letter and took revenue from readers, not the rated. Standards funded by transparency outlast those funded by access.

The letter scale became global infrastructure: Moody's, Standard & Poor's and Fitch still control roughly 95% of the ratings business, and US regulators have formally relied on their judgments since the mid-1970s. The darker sequel came when agencies shifted from investor-pays to issuer-pays in the 1970s; the same letters that built trust stamped AAA on subprime securities before 2008. Reforms since have tried to reduce reliance on ratings, yet the A-through-C vocabulary remains how the world's credit is quoted.