The biggest difference here is the overweight in BBB-rated bonds for both ETFs versus that of the index. This is a function of the issuers (via the index) quantifying stronger issuers (by their metrics) and higher relative value in that rating bucket.
This differential is also evidenced by comparing the underlying industry exposure using the Barclays classification schema.
A couple differences of note:
- CBND has a smaller industry divergence versus the broad index, with one exception being a higher REIT and lower Bank exposure
- WFIG has a bit more divergence, particularly in the overweighting to industrials (i.e., in the Telecom and Non-Cyclicals)
One commonly raised drawback of the traditionally weighted indices/ETFs is that the companies that issue the most debt have the highest weighting. While not always the case, this increased issuance may be of detriment to the issuer quality. These alternatively weighted ETFs have the flexibility to reduce said weighting if deemed necessary by the process. In the example above, CBND has a much lower weighting to banks, which is the largest industry exposure in the index due to common names such as Bank of America and JP Morgan. This also brings about a difference in methodology between the ETFs. While Bank of America is one of CBNDs largest underweights relative to the index, WFIG is actually overweight the issuer by nearly 1.5%.
The logical next question is if this alternative weighting adds value. To examine the question I looked at the total return and excess returns series for the CBND index (ISCU) compared to that of LUAC, allowing for an apples-to-apples comparison. Since the ISCU inception in March 2008 through the end of August 2016, the ISCU index outperformed LUAC by 3% on a total return basis (71.3% vs 68.3% cumulative). Additionally, ISCU had an additional excess return of about 4% cumulative, meaning the total return differences were not just a function of a different duration profile. Additionally, a majority of the months in which ISCU had a stronger relative excess return came out of the bottom of the 07-09 bear market.
As is common knowledge by now, the smart beta craze has taken over the equity space. While there are names available in the fixed income ETF space, adoption has been slow. It may just be that a catalyst is needed to get investors out of what may be deemed a fixed income complacency and to spark their interest. Hopefully, however, such interests are sparked before the benefits of an alternatively weighted ETF are in the rearview mirror.