Credit ratings are backward looking measures of revolving debt, open, and installment loans:

Installment Debt – Installment debt is money owed to a creditor who expects repayment over a fixed period of time made in equal monthly amounts. A mortgage or a car loan is an example of installment debt. The debtor is making the same payment over a fixed schedule of time. An auto loan, for example, might call for 48 equal payments of $300. A home loan might call for the same payment of $1000 every month for 30 years. These loans are all paid off in installments.

Revolving Debt – Revolving debt is money owed to a creditor who sets the monthly payment based on the current balance. Credit cards, lines of credit, or retail store cards are examples of revolving credit. Each month the balance of credit available varies based on the debtor’s activity from the previous month and any unpaid amount rolled over or “revolved.”

Open Debt – Open debt is the least common type of debt and means that each month the debtor can run up a balance and is expected to pay it in full when the bill is due. A cell phone is a good example of open debt. The American Express Green Card is another example of open debt. There is no predefined credit limit and the balance must be paid in full each month.

The letter “R” refers to a revolving debt, “I” stands for instalment debt, and “O” stands for open debt. The numbers range from 0 (too new to rate) to 9 (bad debt or placed for collection or bankruptcy.) 

For a revolving debt, an R1 rating is the notation to have. That signifies that the creditor pays their bills within 30 days, or “as agreed.”  Similarly for instalment and open debt, an I1 or O1 rating is top-tier. For example, a 90 day GIC from the Royal Bank of Canada would carry an R1 rating and a 5 year Canada Savings Bond would carry an I1 rating.

FICO is a standardized method of aggregating credit ratings.  It is widely used in the USA and Canada to establish credit ratings for individuals, but the concepts can be applied to corporations too.

FICO scores are weighted summaries of:

• 35% Payment History (proportion paid on time, etc)
• 30% Total Amount Owed (amount owning accross different types of accounts)
• 15% Length of Credit History (time since accounts opened, time since last activity)
• 10% New Credit Applied For (number of recently opened accounts and proporation of accouts recently opened by type of credit account)
• 10% Types of Credit Used (number of credit cards, retail accounts, installment loans, mortgage, consumer finance accounts, etc.)

The resulting FICO score is on a scale of 300 – 900 where a higher score represents higher credit quality and usually results in a lower interest rate for the credit applied for.  For example, a $150 K mortgage with a 30 year term under different FICO scores could range from 5.5 – 7.25% as shown below:

By law in both Canada and the USA you can get a copy of your own credit rating for free by mail (or immediately via online purchase).  There are two main credit bureaus in Canada: Equifax Canada and TransUnion Canada.

You can also use FICO score calculators to estimate your credit score.

This page by Reuter’s Bond Channel shows the real time view of interest rate spreads over US treasuries (which currently are assumed to be of zero risk).

The page shows how interest rates vary both by time and by quality.

Note the links at the bottom of the page that allow you to toggle between different types of bonds using the Dow Theory categories.

Interest rate spreads are measured using Basis Points, where 1 Basis Point = 1/100 of 1%.  In other words, 100 basis points = 1%.