@article {Keller88, author = {Ulrich Keller and Andreas Schlatter}, title = {Telescopic Sums}, volume = {9}, number = {2}, pages = {88--92}, year = {1999}, doi = {10.3905/jfi.1999.319264}, publisher = {Institutional Investor Journals Umbrella}, abstract = {Performance attribution of bond portfolios has always been a complex mater. Especially during times when monetary unions such as the EMU materialize, it has become more important to incorporate in to an attribution next to duration and yield curve also the factor selection. At the same time, given the fact that more and more corporate bonds are emitted, a performance attribution of a bond portfolio has to be independent of any yield curve other than the portfolio{\textendash}implied curve. In this article, we develop a linear model based on the portfolio implied yield curve, which distributed the excess return of a bond portfolio to the factors duration, yield curve, and selection. The model is easily applicable and has a geometric visualization in form of a {\textquotedblleft}double pie.{\textquotedblright}}, issn = {1059-8596}, URL = {https://jfi.pm-research.com/content/9/2/88}, eprint = {https://jfi.pm-research.com/content/9/2/88.full.pdf}, journal = {The Journal of Fixed Income} }