A firm paid to make a hierarchical judgement about how risky an asset, usually debt in some form, is. Different rating agencies use different terminology. Three firms dominate the market - Moodys, S&P and Fitch.
<table class="wikitable">
<tbody>
<tr>
<th colspan="2">Moody's</th>
<th colspan="2">S&amp;P</th>
<th colspan="2">Fitch</th>
<th colspan="2" rowspan="2">Rating description</th>
</tr>
<tr>
<th>Long-term</th>
<th>Short-term</th>
<th>Long-term</th>
<th>Short-term</th>
<th>Long-term</th>
<th>Short-term</th>
</tr>
<tr>
<td>Aaa</td>
<td rowspan="6">P-1</td>
<td>AAA</td>
<td rowspan="4">A-1+</td>
<td>AAA</td>
<td rowspan="4">F1+</td>
<td>Prime</td>
<td rowspan="10">Investment-grade</td>
</tr>
<tr>
<td>Aa1</td>
<td>AA+</td>
<td>AA+</td>
<td rowspan="3">High grade</td>
</tr>
<tr>
<td>Aa2</td>
<td>AA</td>
<td>AA</td>
</tr>
<tr>
<td>Aa3</td>
<td>AA−</td>
<td>AA−</td>
</tr>
<tr>
<td>A1</td>
<td>A+</td>
<td rowspan="2">A-1</td>
<td>A+</td>
<td rowspan="2">F1</td>
<td rowspan="3">Upper medium grade</td>
</tr>
<tr>
<td>A2</td>
<td>A</td>
<td>A</td>
</tr>
<tr>
<td>A3</td>
<td rowspan="2">P-2</td>
<td>A−</td>
<td rowspan="2">A-2</td>
<td>A−</td>
<td rowspan="2">F2</td>
</tr>
<tr>
<td>Baa1</td>
<td>BBB+</td>
<td>BBB+</td>
<td rowspan="3">Lower medium grade</td>
</tr>
<tr>
<td>Baa2</td>
<td rowspan="2">P-3</td>
<td>BBB</td>
<td rowspan="2">A-3</td>
<td>BBB</td>
<td rowspan="2">F3</td>
</tr>
<tr>
<td>Baa3</td>
<td>BBB−</td>
<td>BBB−</td>
</tr>
<tr>
<td>Ba1</td>
<td rowspan="14">Not prime</td>
<td>BB+</td>
<td rowspan="6">B</td>
<td>BB+</td>
<td rowspan="6">B</td>
<td rowspan="3">Non-investment grade
speculative</td>
<td rowspan="14">Non-investment grade
AKA high-yield bonds
AKA junk bonds</td>
</tr>
<tr>
<td>Ba2</td>
<td>BB</td>
<td>BB</td>
</tr>
<tr>
<td>Ba3</td>
<td>BB−</td>
<td>BB−</td>
</tr>
<tr>
<td>B1</td>
<td>B+</td>
<td>B+</td>
<td rowspan="3">Highly speculative</td>
</tr>
<tr>
<td>B2</td>
<td>B</td>
<td>B</td>
</tr>
<tr>
<td>B3</td>
<td>B−</td>
<td>B−</td>
</tr>
<tr>
<td>Caa1</td>
<td>CCC+</td>
<td rowspan="5">C</td>
<td rowspan="5">CCC</td>
<td rowspan="5">C</td>
<td>Substantial risks</td>
</tr>
<tr>
<td>Caa2</td>
<td>CCC</td>
<td>Extremely speculative</td>
</tr>
<tr>
<td>Caa3</td>
<td>CCC−</td>
<td rowspan="3">Default imminent with little
prospect for recovery</td>
</tr>
<tr>
<td rowspan="2">Ca</td>
<td>CC</td>
</tr>
<tr>
<td>C</td>
</tr>
<tr>
<td>C</td>
<td rowspan="3">D</td>
<td rowspan="3">/</td>
<td>DDD</td>
<td rowspan="3">/</td>
<td rowspan="3">In default</td>
</tr>
<tr>
<td rowspan="2">/</td>
<td>DD</td>
</tr>
<tr>
<td>D</td>
</tr>
</tbody>
</table>