Source: Wikipedia - Bond Credit Rating

Moody's S&P Fitch Rating description
Long-term Short-term Long-term Short-term Long-term Short-term
Aaa P-1 AAA A-1+ AAA F1+ Prime Investment-grade
Aa1 AA+ AA+ High grade
Aa2 AA AA
Aa3 AA− AA−
A1 A+ A-1 A+ F1 Upper medium grade
A2 A A
A3 P-2 A− A-2 A− F2
Baa1 BBB+ BBB+ Lower medium grade
Baa2 P-3 BBB A-3 BBB F3
Baa3 BBB− BBB−
Ba1 Not prime BB+ B BB+ B Non-investment grade
speculative
Non-investment grade
aka high-yield bonds
aka junk bonds
Ba2 BB BB
Ba3 BB− BB−
B1 B+ B+ Highly speculative
B2 B B
B3 B− B−
Caa1 CCC+ C CCC C Substantial risks
Caa2 CCC Extremely speculative
Caa3 CCC− Default imminent with little
prospect for recovery
Ca CC
C
C D / DDD / In default
/ DD
D


Moody's Standard & Poor's Fitch Credit worthiness
Aaa AAA AAA An obligor has EXTREMELY STRONG capacity to meet its financial commitments.
Aa1 AA+ AA+ An obligor has VERY STRONG capacity to meet its financial commitments. It differs from the highest-rated obligors only to a small degree.
Aa2 AA AA
Aa3 AA− AA−
A1 A+ A+ An obligor has STRONG capacity to meet its financial commitments but is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligors in higher-rated categories.
A2 A A
A3 A− A−
Baa1 BBB+ BBB+ An obligor has ADEQUATE capacity to meet its financial commitments. However, adverse economic conditions or changing circumstances are more likely to lead to a weakened capacity of the obligor to meet its financial commitments.
Baa2 BBB BBB
Baa3 BBB− BBB−
Ba1 BB+ BB+ An obligor is LESS VULNERABLE in the near term than other lower-rated obligors. However, it faces major ongoing uncertainties and exposure to adverse business, financial, or economic conditions which could lead to the obligor's inadequate capacity to meet its financial commitments.
Ba2 BB BB
Ba3 BB− BB−
B1 B+ B+ An obligor is MORE VULNERABLE than the obligors rated 'BB', but the obligor currently has the capacity to meet its financial commitments. Adverse business, financial, or economic conditions will likely impair the obligor's capacity or willingness to meet its financial commitments.
B2 B B
B3 B− B−
Caa CCC CCC An obligor is CURRENTLY VULNERABLE, and is dependent upon favourable business, financial, and economic conditions to meet its financial commitments.
Ca CC CC An obligor is CURRENTLY HIGHLY-VULNERABLE.
C C The obligor is CURRENTLY HIGHLY-VULNERABLE to nonpayment. May be used where a bankruptcy petition has been filed.
C D D An obligor has failed to pay one or more of its financial obligations (rated or unrated) when it became due.
e, p pr Expected Preliminary ratings may be assigned to obligations pending receipt of final documentation and legal opinions. The final rating may differ from the preliminary rating.
WR Rating withdrawn for reasons including: debt maturity, calls, puts, conversions, etc., or business reasons (e.g. change in the size of a debt issue), or the issuer defaults. [3]
Unsolicited Unsolicited This rating was initiated by the ratings agency and not requested by the issuer.
SD RD This rating is assigned when the agency believes that the obligor has selectively defaulted on a specific issue or class of obligations but it will continue to meet its payment obligations on other issues or classes of obligations in a timely manner.
NR NR NR No rating has been requested, or there is insufficient information on which to base a rating.