WARF (Weighted Average Rating Factor)
Definition
WARF, the weighted average rating factor, is a single number that summarizes the credit quality of a CLO's loan portfolio. Each loan's credit rating is converted to a numerical factor on Moody's scale, where Aaa is 1, Baa3 is 610, B2 is 2,720 and Caa3 is 8,070, and the factors are averaged with each loan weighted by its par amount. A lower WARF means a higher-quality pool. Most broadly syndicated loan CLOs run a WARF between 2,500 and 3,000, which sits between the B1 and B3 factors, and their indentures cap it at a stated maximum.
Why it matters
WARF is one of the binding covenant tests in a CLO indenture. The manager must keep the pool's WARF at or below a stated maximum, typically 2,800 to 3,000 for broadly syndicated loan CLOs, or lose trading flexibility, even with no defaults in the pool. That creates the central tension of CLO management: lower-rated loans pay more spread and raise WARF, higher-rated loans lower WARF and pay less. Reading a CLO's WARF against its limit, and watching which way it drifts, tells you whether the manager is reaching for yield or trading up in quality. For investors in CLO equity funds such as Eagle Point Credit or Oxford Lane, WARF is one of the portfolio statistics reported alongside the OC cushion and the CCC bucket, and it is the one that moves first when a manager changes course.
Common misconceptions
- •WARF is not a default probability. The factors track Moody's idealized default rates, but a WARF of 3,000 is a rating mix around B2 to B3, not a 30 percent chance of default.
- •Different agencies use different systems. WARF is Moody's methodology; Fitch has its own factor scale and S&P tests scenario default rates instead. A pool can pass one agency's test and fail another's.
- •Split ratings complicate the number. A loan rated B1 by Moody's and B+ by S&P may be counted at the lower rating, at Moody's rating, or at a derived rating depending on the indenture. The definition section of the indenture says which.
- •WARF can worsen without downgrades. Rotating from BB loans into performing B loans raises WARF; the pool's fundamentals may be unchanged. The reverse also holds: ratings lag, so WARF can improve while credit is deteriorating.
Technical details
Moody's rating factor table (WARF scale)
Aaa: 1
Aa1: 10
Aa2: 20
Aa3: 40
A1: 70
A2: 120
A3: 180
Baa1: 260
Baa2: 360
Baa3: 610
Ba1: 940
Ba2: 1,350
Ba3: 1,766
B1: 2,220
B2: 2,720
B3: 3,490
Caa1: 4,770
Caa2: 6,500
Caa3: 8,070
Ca: 9,998
C: 10,000
The scale is non-linear. Moving from Baa2 to Baa3 adds 250 points; moving from B2 to B3 adds 770; moving from B3 to Caa1 adds 1,280. The factors are calibrated to Moody's idealized cumulative default rates over ten years, which is why each notch below investment grade costs more than the one above it.
WARF formula and a worked example
WARF = sum of (par amount of each loan x rating factor) divided by total par amount.
Example: a $500 million pool holds $200 million of B2 loans (factor 2,720), $200 million of B1 loans (2,220) and $100 million of Ba3 loans (1,766).
(200 x 2,720) + (200 x 2,220) + (100 x 1,766) = 544,000 + 444,000 + 176,600 = 1,164,600.
1,164,600 divided by 500 = 2,329. The pool's WARF is 2,329, comfortably below a 2,800 to 3,000 limit.
Defaulted loans are usually excluded from the WARF calculation and handled by the OC test at their recovery value instead, so a rising default count can leave WARF flat while the OC cushion falls. Read the two together.
Typical WARF limits by CLO type
Broadly syndicated loan (BSL) CLOs: maximum WARF of about 2,800 to 3,000, with most pools running 2,500 to 2,900.
Middle-market CLOs: limits of about 3,200 to 3,600, because the underlying borrowers are smaller and rated lower.
European CLOs: about 2,900 to 3,100, similar to US BSL deals.
Vintage matters. Pre-2008 deals often allowed 3,200 or more; post-crisis structures tightened to 2,750 to 2,850; 2020 to 2024 BSL deals cluster around 2,800 to 2,900. The exact figure is negotiated per deal and appears in the indenture's collateral quality tests.
Many indentures use a WARF matrix rather than a single number: the manager may choose a higher WARF in exchange for a higher weighted average spread or a higher diversity score, within a grid the rating agency approved.
What a WARF limit does to manager behaviour
A pool sitting a few points under its limit cannot add a lower-rated loan without selling a higher-rated one, whatever the price on offer. This is why CLO managers often become forced sellers of loans on their way to a downgrade: the covenant, not the credit view, forces the trade.
In benign markets WARF drifts higher as managers reach for spread. In stress, it often falls as managers rotate into quality even while prices are dropping, and because ratings lag, the number can improve while the pool is actually weakening. The CCC bucket and the OC cushion are the corrective reads.
WARF and actual credit quality
WARF measures the rating mix, not recovery prospects or concentration. Two pools with a WARF of 2,500 can differ completely: one all B1 loans in stressed industries with 50 percent expected recoveries, the other a spread of Ba3 and B2 loans across diverse industries with 70 percent recoveries. The second has the higher WARF and the better fundamentals.
That is why CLO equity analysis pairs WARF with the diversity score, obligor and industry concentration limits, the CCC bucket, and the junior OC cushion rather than reading it alone.
Frequently asked questions
- What does WARF mean?
- WARF stands for weighted average rating factor. It converts every loan rating in a CLO portfolio into a number on Moody's rating factor scale and averages those numbers weighted by loan size. It is the standard one-number summary of a CLO pool's credit quality, and a lower WARF is better.
- What is a good WARF?
- There is no universal good number, only the limit written into a CLO's indenture and where the pool sits against it. Broadly syndicated loan CLOs typically carry a maximum WARF of about 2,800 to 3,000 and run a few hundred points below it. A pool at 2,300 is mostly B1 and better; a pool at 3,000 is a B2 to B3 average. Middle-market CLOs run higher, often with limits of 3,200 to 3,600.
- How is WARF calculated?
- Multiply each loan's par amount by its Moody's rating factor, add the products, and divide by total par. A $500 million pool with $200 million rated B2 (factor 2,720), $200 million rated B1 (2,220) and $100 million rated Ba3 (1,766) has a WARF of 2,329.
- What is the Moody's WARF table?
- Moody's assigns a factor to each rating notch: Aaa 1, Aa1 10, Aa2 20, Aa3 40, A1 70, A2 120, A3 180, Baa1 260, Baa2 360, Baa3 610, Ba1 940, Ba2 1,350, Ba3 1,766, B1 2,220, B2 2,720, B3 3,490, Caa1 4,770, Caa2 6,500, Caa3 8,070, Ca 9,998, C 10,000. The scale is not linear: each notch below investment grade adds far more than the notch above it.
- Does WARF measure default probability?
- Not directly. The factors are calibrated to Moody's idealized ten-year default rates, so a higher WARF corresponds to a higher expected default rate, but the relationship is not a percentage. A WARF of 3,000 does not mean a 30 percent default probability.
- Do S&P and Fitch use WARF?
- WARF as a covenant test is Moody's methodology. Fitch publishes its own weighted average rating factor with a different scale, and S&P's CLO methodology tests portfolio credit quality through scenario default rates rather than a rating factor. A pool can satisfy Moody's WARF test and be constrained by a different agency's test in the same indenture.
- Can WARF rise without any downgrades?
- Yes. If a manager sells BB loans and buys B loans that are all performing, WARF rises even though no credit event occurred. WARF reflects the rating mix the manager chooses as much as the credit cycle.