What are bond ratings?

A bond rating measures the creditworthiness of a bond based on the issuer’s financial strength or ability to pay a bond’s principal and interest. The rating is typically assigned as a letter grade indicating the bond’s credit quality.

Bond ratings are assigned by private independent rating services, such as Standard & Poor’s (S&P’s), Moody’s Investors Service, and Fitch Ratings Inc. These three agencies control nearly 95% of the bond rating market share.

Bond ratings are important as they can help institutional investors assess the risk and potential returns of a bond investment.

How are bond ratings determined?

Bond ratings are determined through a comprehensive financial analysis of the bond’s issuing body, whether it’s the U.S. Treasury or an international corporation. Each rating agency uses a different set of criteria to determine their ratings, however bond ratings usually involve assessing;

• Financial strength: The issuer’s ability to generate cash flow to cover debt payments.
• Liquidity: Access to assets or funding to meet short-term obligations.
• Market conditions: Broader economic trends that might affect the issuer’s financial stability.
• Future outlook: Predictions regarding the issuer's ability to sustain or improve its creditworthiness over time.

The agencies then provide a letter-grade rating based on their analyses. S&P’s and Fitch use a scale ranging from AAA (highest credit quality) to D (default). Moody’s follows a similar system, with ratings ranging from Aaa (highest) to C (lowest).

The role of rating agencies in the bond market

Rating agencies, like Standard & Poor’s (S&P), Moody’s, and Fitch Ratings, play an important role in the bond market by providing independent assessments of a bond issuer’s creditworthiness – which is essential for risk management services.

These agencies conduct thorough evaluations of an issuer’s ability to meet its financial obligations, such as paying the principal and interest on time. Based on their evaluations, they assign bonds with a letter rating. This process provides a consistent classification of bonds that investors often use to guide their decision-making.

The three biggest rating agencies are:

• S&P Global Bond Ratings: S&P is the oldest credit rating agency, with ratings covering more than one million government and corporate bonds, structured finance entities, and securities.
• Fitch Ratings: Fitch has a fairly limited market share compared to the ‘Big Three’ agencies. The agency covers various sectors, from financial institutions to insurance companies and corporate finance.
• Moody’s Investors Service Bond Ratings: Moody’s ratings have covered thousands of issuers from sovereign nations to financial institutions and public finance issuers.

What are the main categories of bond ratings?

There are two main categories of bond ratings: investment-grade and non-investment grade (also known as high-yield or junk bonds). Each of these categories can then be narrowed down into subcategories based on the rating agency’s classification.

Investment-grade bonds

These are considered the safest as they have the lowest risk of default. However, they also provide the smallest yields. Investment-grade bonds have a minimum rating of BBB- (on S&P’s and Fitch’s scales) or Baa3 (on Moody’s scale). They’re often held by conservative investors seeking stable returns with minimal risk, such as pension funds or insurance companies.

Non-investment grade bonds

These bonds are considered speculative, offering higher risk but also higher yields. They’re sometimes referred to as ‘high-yield’ or ‘junk’ bonds. Any bond with a rating below BBB- or Baa3 is considered non-investment grade.

Bonds rating chart

The table below gives an overview of bond categories based on ratings by S&P, Fitch, and Moody’s.

S&P’s	Fitch	Moody's	Grade	Risk
AAA	AAA	Aaa	Investment-Grade	Lowest Risk
AA+/AA/AA-	AA+/AA/AA-	Aa1/Aa2/Aa3	Investment-Grade	Low Risk
A+/A/A-	A+/A/A-	A1/A2/A3	Investment-Grade	Low Risk
BBB+/BBB/BBB-	BBB+/BBB/BBB-	Baa1/Baa2/Baa3	Non-Investment Grade	Medium Risk
BB+/BB/B-/B+/B/B-	BB+/BB/B-/B+/B/B-	Ba1/Ba2/Ba3/B1/B2/B3	Non-Investment Grade	High Risk
CCC+/CCC/CCC-/CC	CCC+/CCC/CCC-/CC	Caa1/Caa2/Caa3/Ca	Non-Investment Grade	Highest Risk
C/D	C/D	C	Non-Investment Grade	In or Near Default

The table provides an example of how a bond rating determines an issuer’s creditworthiness, using descriptions from S&P’s:

Rating	Creditworthiness
AAA	Extremely strong capacity to meet financial obligations.
AA	Very strong capacity to meet financial obligations.
A	Strong capacity to meet financial obligations, but somewhat susceptible to adverse economic conditions and changes in circumstances.
BBB	Adequate capacity to meet financial commitments, but more subject to adverse economic conditions.
BB	Less vulnerable in the near-term but faces major ongoing uncertainties to adverse business, financial, and economic conditions.
B	More vulnerable to adverse business, financial, and economic conditions but currently has the capacity to meet financial commitments.
CCC	Currently vulnerable and dependent on favorable business, financial, and economic conditions to meet financial commitments.
CC	Highly vulnerable; default has not yet occurred but is expected to be a virtual certainty.
C	Currently highly vulnerable to non-payment with minimal chance of fully recovering funds.
D	Payment on a financial commitment or breach of an imputed promise; also used when a bankruptcy petition has been filed or similar action taken.
NR	The security was not rated.

How bond ratings impact institutional investment decisions

Bond ratings play a valuable role in institutional investment as they offer a way to assess credit risk and guide decision-making. 

Investors often look at bond ratings to assess the quality and stability of bonds before they invest in them. They may also monitor bond ratings regularly to guide decisions about buying, selling, or holding bonds. Bond ratings can shift with an issuer’s financial health, leading rating agencies or downgrade or upgrade a bond’s rating accordingly. These changes can influence institutional investment decisions. For example:

• If an investment-grade bond is downgraded to a lower status, institutional investors with mandates restricting high-risk assets may be forced to sell. When a bond is downgraded to a lower rating, its price could decrease and its yields may increase.
• If a non-investment grade bond is upgraded to investment-grade, it could signal reduced risk. This can increase demand for the bond and potentially raise its market price while lowering its yield.

How bond ratings influence bond pricing and yield

Bond ratings have a direct impact on both bond pricing and yield, as they reflect the perceived creditworthiness of the issuer. Understanding this relationship is important for institutional investors navigating the fixed-income market.

Investment-grade bonds, which are considered safer with a lower risk of default, often command higher prices. However, they also offer lower yields because investors are willing to accept reduced returns in exchange for greater security.

Non-investment grade bonds, which are considered riskier, are often associated with lower prices and higher yields. This is because issuers must offer more attractive returns to compensate investors for the added risk.

This material is for informational purposes only and should not be considered as an investment recommendation or a personal recommendation.