US 7,249,079 B1 · Method and system for multi-period performance attribution

Abstract

A method for arithmetic and geometric performance attribution which accurately links single-period attribution effects over multiple periods. The arithmetic attribution method optimally distributes the residual to yield a minimum-distortion residual-free arithmetic attribution system. The geometric attribution method defines the attribution effects in terms of ratios. The arithmetic method determines portfolio performance over multiple time periods as a sum of terms of form (Rt− Rt)(A+αt), where the coefficients αt are defined as α t = [ R - R _ - A ⁢ ∑ k = 1 T ⁢ ( R k - R _ k ) ∑ k = 1 T ⁢ ( R k - R _ k ) 2 ] ⁢ ( R t - R _ t ) . The value of A is A = 1 T ⁡ [ ( R - R _ ) ( 1 + R ) 1 / T - ( 1 + R _ ) 1 / T ] , where R≠ R, or, for the special case of R= R, A=(1+R)(T−1)/T, where T is the number of time periods. In all embodiments, the inventive coefficient (A+αt) have smaller (typically much smaller) standard deviation than conventional logarithmic coefficients, which reduces variation in the weights assigned to each time period relative to the other time periods in the attribution calculation. The geometric method determines portfolio relative performance over multiple time periods as 1 + R 1 + R _ = ∏ t = 1 T ⁢ ∏ i = 1 N ⁢ ( 1 + I it G , Vestek ) ⁢ ( 1 + S it G , Vestek ) , where 1 + I it G , Vestek = ( 1 + w it ⁢ r it 1 + w it ⁢ r _ it ) ⁢ Γ t is the geometric issue selection and 1 + S it G , Vestek = ( 1 + w it ⁢ r _ it 1 + w _ it ⁢ r _ it ) ⁢ ( 1 + w _ it ⁢ R _ t 1 + w it ⁢ R _ t ) ⁢ Γ t is the geometric sector selection, with Γ t = [ ( 1 + R t 1 + R _ t ) ⁢ ∏ j = 1 N ⁢ ( 1 + w _ jt ⁢ r _ jt ) ⁢ ( 1 + w jt ⁢ R _ t ) ( 1 + w jt ⁢ r jt ) ⁢ ( 1 + w _ jt ⁢ R _ t ) ] 1 2 ⁢ ⁢ N . The attribution effects employed in the invention geometric attribution method have more natural form than the conventional counterparts, and allow geometric attribution to be performed more accurately. Other aspects of the invention are a computer system programmed to perform any embodiment of the inventive method, and a computer readable medium which stores code for implementing any embodiment of the inventive method.

Claims8

Dependent claims

A computer system, comprising:

a processor which performs an arithmetic performance attribution computation to determine portfolio performance, relative to a benchmark, over multiple time periods t, where t varies from 1 to T, by determining coefficients (A+αt), where A is a coefficient, the values αt are defined as
α
t
=
[
R
-
R
_
-
A
⁢
∑
k
=
1
T
⁢
(
R
k
-
R
_
k
)
∑
k
=
1
T
⁢
(
R
k
-
R
_
k
)
2
]
⁢
(
R
t
-
R
_
t
)
,
where Rt is a portfolio return for period t, Rt is a benchmark return for period t, Rk is a portfolio return for period k, Rk is a benchmark return for period k, k varies from 1 to T, Rk=Rt for k=t, Rk= Rt for k=t, R is determined by
R
=
[
∑
t
=
1
T
⁢
(
1
+
R
t
)
]
-
1
,
and R is determined by
R
_
=
[
∏
t
=
1
T
⁢
(
1
+
R
_
t
)
]
-
1
;
and determining the portfolio relative performance as
R
-
R
_
=
∑
t
=
1
T
⁢
∑
i
=
1
N
⁢
(
A
+
α
t
)
⁢
(
I
it
A
+
S
it
A
)
,
where IitA is an issue selection for sector i and period t, SitA is a sector selection for sector i and period t, and i ranges from 1 to N;
and
a display device coupled to the processor for displaying a result of the arithmetic performance attribution computation.

129 more elements

Dependencies are inferred from the claim text.

Method and system for multi-period performance attribution

Life of this patent

Method and system for multi-period performance attribution

Life of this patent

Abstract

Claims8