A more thorough explanation:

Moody's Investor's Service is a company that helps people make investment decisions. They analyze businesses and give them a rating based on their financial strength. The rating goes from Aaa (the strongest) to C (the weakest). The rating can also have a number from 1 to 3 to show how the business compares to others in the same industry.

For example, if Moody's gives a business a rating of Aa1, it means the business is very strong financially and is better than other businesses with a rating of Aa2 or Aa3.

Another example is if Moody's gives a business a rating of Baa3, it means the business is not as strong financially and is worse than businesses with a rating of Baa2 or Baa1.

Moody's helps investors make informed decisions by providing them with information about the financial strength of businesses. This can help investors decide which businesses to invest in and which ones to avoid.