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Understanding Credit Rating Agencies: Role, History, & Key Players

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Updated October 22, 2025

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Credit rating agencies (CRAs) assess how likely countries and companies are to repay their debts. Their ratings help investors decide where to put their money and influence borrowing costs around the world. The industry is dominated by three major agencies: Moody’s, Standard & Poor’s, and Fitch. These ratings affect government and corporate bonds and shape economic and financial decisions on a global scale.

Key Takeaways

Credit rating agencies provide letter grades to assess the creditworthiness of companies and countries.
The three leading credit rating agencies globally are Moody's, Standard & Poor's, and Fitch.
Credit ratings influence investors' decisions on bonds, debt instruments, and fixed-income securities.
Regulatory and economic changes have driven the development of credit rating agencies over time.
The Credit Rating Agency Reform Act of 2006 and the Dodd-Frank Act of 2010 expanded the SEC's oversight of CRAs.

What Are Credit Ratings?

Countries are issued sovereign credit ratings. This rating analyzes the general creditworthiness of a country or foreign government. Sovereign credit ratings measure the overall economic conditions of a country, including the volume of foreign, public, and private investment, capital market transparency, and foreign currency reserves.

Ratings also assess conditions such as overall political stability and the level of economic stability a country will maintain during a political transition. Institutional investors rely on sovereign ratings to qualify and quantify the general investment atmosphere of a particular country.

Credit, debt, or bond ratings are issued to individual companies and specific classes of individual securities, such as preferred stock, corporate bonds, and various government bonds. Ratings can be assigned separately to both short-term and long-term obligations. Three agencies, Moody's, Standard & Poor's, and Fitch, control nearly the entire credit rating market.

Understanding Fitch Ratings: History and Impact

Fitch operates in New York and London, basing ratings on company debt and its sensitivity to changes like interest rates. Countries request Fitch and other agencies to evaluate their financial situation and political and economic climates. John Knowles Fitch founded the Fitch Publishing Company in 1913 to provide financial statistics for the investment industry via "The Fitch Stock and Bond Manual" and "The Fitch Bond Book."

In 1924, Fitch introduced the AAA through D rating system that has become the basis for ratings throughout the industry. Its credit rating scale for issuers and issues includes investment grade ‘AAA’ to ‘BBB’ and ‘BB’ to ‘D’ as speculative grade with an additional +/- for AA through CCC levels indicating the probability of default or recovery.

An In-Depth Look at Moody's Investors Service: Origins and Methodology

Moody's assigns countries and company debt letter grades differently from Fitch. Investment grade debt goes from Aaa, the highest, to Baa3, where the debtor can repay short-term debt. Below investment grade is speculative-grade debt, which is often referred to as high-yield or junk. These grades range from Ba1 to C, with the likelihood of repayment dropping as the letter grade goes down.

John Moody and Company first published "Moody's Manual" in 1900 with basic statistics and general information about stocks and bonds of various industries. From 1903 until the stock market crash in 1907, "Moody's Manual" was a national publication. In 1909, Moody began publishing "Moody's Analyses of Railroad Investments," which added analytical information about the value of securities. Expanding this idea led to the 1914 creation of Moody's Investors Service to provide ratings for nearly all government bond markets. In the 1970s and late '80s, Moody's began rating commercial paper and bank deposits, becoming the full-scale rating agency it is today.

Exploring Standard & Poor's: Evolution and Credit Rating System

S&P has ten letter-based ratings where 'AA' to 'CCC' may be modified with plus or minus symbols. Anything rated AAA to BBB- is considered investment grade, or the ability to repay debt. Debt rated as BB+ to D is considered speculative, with an uncertain future. The lower the rating, the more potential it has to default, with a D rating as the worst.

Henry Varnum Poor first published the "History of Railroads and Canals in the United States" in 1860, the forerunner of securities analysis and reporting that would be developed over the next century. Standard Statistics was formed in 1906, which published corporate bonds, sovereign debt, and municipal bond ratings. Standard Statistics merged with Poor's Publishing in 1941 to form Standard and Poor's Corporation, which was acquired by The McGraw-Hill Companies in 1966.

Standard and Poor's has become best known by indexes such as the S&P 500, a stock market index that is both a tool for investor analysis and decision-making and a U.S. economic indicator.

U.S. Credit Downgrades

In August 2023, Fitch Ratings downgraded the long-term ratings of the United States to "AA+" from "AAA" based on the expected fiscal deterioration over the next three years, a high and growing general government debt burden, and the erosion of governance relative to "AA" and "AAA" peers over the last two decades with repeated debt limit standoffs and untimely resolutions.

In November of 2023, Moody's, too, downgraded America's credit outlook from "stable" to "negative," citing growing deficits and the national debt.

How Ratings and NRSROs Shape Capital Markets

By 1970, credit rating agencies recognized that objective credit ratings significantly helped issuers. Ratings facilitated access to capital by increasing a securities issuer's value in the marketplace and decreasing the costs of obtaining capital. Expansion and complexity in the capital markets, coupled with an increasing demand for statistical and analytical services, led to the industry-wide decision to charge issuers of securities fees for rating services.

In 1975, financial institutions such as commercial banks and securities broker-dealers sought to soften the capital and liquidity requirements passed down by the Securities and Exchange Commission (SEC). As a result, nationally recognized statistical ratings organizations (NRSROs) were created. Financial institutions could satisfy their capital requirements by investing in securities that received favorable ratings from one or more NRSROs.

The increased demand for rating services by investors and securities issuers, combined with increased regulatory oversight, has led to growth and expansion in the credit ratings industry.

Are Credit Rating Agencies Regulated?

The Credit Rating Agency Reform Act of 2006 allowed the SEC to regulate the internal processes, record-keeping, and business practices of CRAs in the U.S. The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, commonly referred to as Dodd-Frank, further grew the regulatory powers of the SEC, including the requirement of a disclosure of credit rating methodologies. In 2009, the EU established a regulatory framework for CRAs. CRAs must register and are supervised by national competent authorities who approve rating methodologies and uphold transparent rating activities. In 2011, the European Securities and Markets Authority (ESMA) was established.

Can Credit Ratings Affect a Country's Economic Stability?

Credit rating agencies came under scrutiny and regulatory pressure following the financial crisis and the Great Recession of 2007 to 2009. It was argued that CRAs provided inaccurate positive ratings, leading to bad investments, and the agencies gave mortgage-backed securities (MBSs) AAA ratings. The agencies were accused of trying to raise profits and their market share in exchange for these inaccurate ratings. This helped lead to the subprime mortgage market collapse that led to the financial crisis.

Why Are There Only Three Leading Credit Rating Agencies?

Some have argued that regulators have helped to prop up an oligopoly in the credit rating industry with rules that act as barriers to entry for small- or mid-sized agencies.

The Bottom Line

Investors expect credit rating agencies to provide objective information using sound analytical methods and accurate statistical measurements, whether this comes from one or multiple credit rating agencies. Regulatory compliance is critical to maintaining market trust and integrity.

Article Sources

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European Securities and Markets Authority. "Report on CRA Market Share Calculation," Page 6.
U.S. Securities and Exchange Commission. "Annual Report on Nationally Recognized Statistical Rating Organizations," Pages 4, 27.
Fitch Ratings. "About Us."
Bank for International Settlements. "To Err Is Human: Rating Agencies and the Interwar Foreign Government Debt Crisis," Pages 30-31.
Fitch Ratings. "About Us."
Fitch Ratings. "Rating Definitions."
Moody's. "Rating Symbols and Definitions," Page 6.
Moody's. "History."
Ahmed Naciri. "Credit Rating Governance: Global Credit Gatekeepers," Pages 45-46. Routledge, 2015.
S&P Global. "Guide to Credit Rating Essentials," PDF Page 9.
S&P Global. "Understanding Ratings."
Fitch Ratings. "Fitch Downgrades the United States' Long-Term Ratings to 'AA+' from 'AAA'."
Reuters. "Moody's turns negative on US credit rating, draws Washington ire."
Organization for Economic Co-operation and Development. "Hearings: Competition and Credit Rating Agencies," Pages 5-7.
Mercatus Center. "A Brief History of Credit Rating Agencies: How Financial Regulation Entrenched this Industry's Role in the Subprime Mortgage Debacle of 2007 - 2008."
U.S. Securities and Exchange Commission. "Credit Rating Agencies."
European Commission. "Regulating Credit Rating Agencies."
Council on Foreign Relations. "The Credit Rating Controversy."
Harvard Law School Forum on Corporate Governance. "What's (Still) Wrong with Credit Ratings?"

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