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BEBR 


FACULTY  WORKING  PAPER  NO.  1144 
College  of  Commerce  and  Business  Administration 
University  of  Illinois  at  Urbana- Champaign 
April,  1985 


Systematic  Risk  and  Market  Power 
An  Application  of  Tobin's  q 


K.  C.  Chen,  Assistant  Professor 
Department  of  Finance 

David  C .  Cheng 
University  of  Alabama 

Gailen  L.  Hite 
Southern  Methodist  University 


Abstract 

We  investigate  the  relationship  between  systematic  risk  and  market 
power  measured  by  Tobin' s  q,  the  ratio  of  market  value  to  replacement 
cost.   We  demonstrate  there  is  a  one-to-one  relationship  between  the 
Tobin' s  q  ratio  and  the  S&T  measure  of  market  power.   Our  theoretical 
model  predicts  that  as  a  firm's  market  power  increases  the  systematic 
risk  will,  ceteris  paribus,  decrease.   Our  empirical  results  ultimately 
confirm  this  negative  association  as  predicted  by  S&T. 


Digitized  by  the  Internet  Archive 

in  2011  with  funding  from 

University  of  Illinois  Urbana-Champaign 


http://www.archive.org/details/systematicriskma1144chen 


Systematic  Risk  and  Market  Power: 
An  Application  of  Tobin's  q 


I.   Introduction 

One  of  the  most  important  advances  in  the  field  of  financial  eco- 
nomics has  been  the  development  of  an  equilibrium  model  of  security 
price  determination  under  uncertainty.   This  model,  known  as  the 
capital  asset  pricing  model  (CAPM) ,  was  developed  by  Sharpe  [1964], 
Lintner  [1965]  and  Mossin  [1966].   The  CAPM  holds  that  securities  will 
be  priced  in  equilibrium  to  yield  an  expected  return  that  is  a  linear 
function  of  the  systematic,  or  non-diversif iable ,  risk.   As  originally 
developed,  the  CAPM  does  not  provide  a  direct  linkage  between  a  firm's 
systematic  risk  and  the  underlying  microeconomic  variables  of  the 
firm,  e.g.,  demand  uncertainty,  input  mix,  market  power,  etc. 

The  lack  of  a  well-defined  model  of  the  determinants  of  systematic 
risk  has  hampered  the  investigation  of  industrial  organization  econo- 
mists in  their  ability  to  interpret  rates  of  return  across  industries 
with  different  market  structures.   It  is  difficult  to  determine  how 
much  of  the  return  variation  is  explained  by  systematic  risk  differen- 
tial and  how  much  is  attributable  to  the  existence  of  market  power. 
Aggravating  this  problem  is  the  fact  that  systematic  risk  itself  may 
be  influenced  by  market  power.   In  fact,  the  work  of  Hurdle  [1974], 
Melicher,  et.  al.  [1976],  Sullivan  [1977,  1982],  and  Curley,  et.  al. 
[1982]  have  produced  mixed  results  as  to  the  direction  and  magnitude 
of  the  relationship  between  systematic  risk  and  market  power. 

One  of  the  difficulties  with  the  empirical  work  stems  from  the 
lack  of  a  precise  measure  of  market  power.   Typically,  concentration 


-2- 

ratios  have  been  used  as  proxies  for  market  power  but  the  difficulty 
of  inferring  the  existence  of  economic  rents  from  mere  concentration 
ratios  is  well-known.  Thus,  the  empirical  work  to  date  sheds  little 
light  on  the  relationship  between  systematic  risk  and  market  power. 
One  of  the  purposes  of  this  paper  is  to  develop  and  test  an  integrated 
model  of  firm  decisions  that  links  systematic  risk  to  a  well-defined 
measure  of  market  power. 

Early  attempts  at  integrating  systematic  risk  and  firm  variables 
may  be  found  in  Thomadakis  [1976],  Hite  [1977],  and,  most  notably, 
Subrahmanyam  and  Thomadakis  [1980].   While  these  papers  vary  widely  in 
approach  and  emphasis,  there  is  general  agreement  that  for  a  given 
level  of  cashflow  risk,  greater  market  power  results  in  lower  systematic 
risk.   As  Subrahmanyam  and  Thomadakis  [1980,  p.  447]  state,  "Thus, 
irrespective  of  the  source  of  uncertainty,  monopoly  power  unambiguously 
reduces  beta." 

In  this  paper  we  model  the  production  and  output  of  a  quantity- 
setting  firm  facing  stochastic  demand.   We  start  with  the  Subrahmanyam 
and  Thomadakis  (henceforth,  S&T)  model  and  develop  a  precise  form  for 
the  relationship  between  systematic  risk  and  market  power.   We  note 
that  if  a  firm  is  earning  economic  rents,  these  will  be  capitalized 
into  the  market  prices  of  the  firm's  outstanding  securities.   The 
existence  of  positive  rents  would  result  in  the  market  value  of  the 
firm  exceeding  the  replacement  cost  of  its  capital  stock.   Using  the 
ratio  of  market  value  to  replacement  cost,  a  ratio  commonly  referred 
to  as  "Tobin's  q,"   we  have  a  measure  of  economic  rents  that  can  be 


mo 


-3- 

re  easily  estimated  than  the  S&T  measure  of  market  power.   We  demon- 
strate there  is  a  one-to-one  relationship  between  the  q-ratio  and  the 
S&T  measure  of  market  power.   Furthermore,  we  confirm  the  negative 
relationship  between  market  power  and  systematic  risk  hypothesized  by 
S&T. 

Tobin  introduced  the  q-ratio  in  an  attempt  to  explain  aggregate 
investment  behavior  in  the  economy.   Thus,  using  q  to  measure  economic 
rents  represents  an  extension  of  Tobin's  concept  to  microeconomic 
analysis.   Recently,  Lindenberg  and  Ross  [1981 J  have  used  q-ratios  to 
measure  economic  rents  and  market  power.   The  current  paper  extends 
the  Lindenberg  and  Ross  insight  to  investigate  the  relationship  between 
market  power  and  systematic  risk.   Our  theoretical  model  predicts  that 
as  a  firm's  market  power  increases  the  systematic  risk  will,  ceteris 
paribus,  decrease.   Our  empirical  results  ultimately  confirm  this 
negative  association  as  predicted  by  S&T. 

The  rest  of  the  paper  is  organized  as  follows.   Section  II  pre- 
sents the  standard  optimization  problem  of  the  firm  in  an  economy  in 
which  uncertain  return  streams  are  priced  according  to  the  single- 
period  CAPM.   We  derive  an  explicit  expression  for  the  firm's  systematic 
risk  as  a  function  of  its  q-ratio.   The  third  section  describes  the 
sample  and  the  estimation  of  the  variables  for  the  empirical  tests. 
Section  IV  contains  our  findings  followed  by  a  short  summary. 


-4- 

II.   The  Model 

A.   Firm  Equilibrium 

Following  the  S&T  approach,  we  consider  a  firm  facing  Che  follow- 
ing stochastic  demand  function: 

P  =  P(Q)(l+e)  (1) 

Here  and  throughout  the  paper  a   indicates  a  random  variable.   The 
function  P(Q)  is  assumed  to  be  a  negatively  sloped  function  but  e  is 
a  random  demand  variable  which  is  independent  of  the  quantity  of  out- 
put with  E(e)  =  0  so  that  E(P)  =  P(Q).   The  marginal  revenue  function 
is  assumed  to  be  given  by 

MR(Q)  =  (l-u)P  (2) 

where  u  is  the  reciprocal  of  the  price  elasticity  of  demand.   Note  that 
(1-u)    is  the  Lerner  index  of  monopoly  power.   The  firm  makes  its  out- 
put decision  before  the  price  is  known,  i.e.,  before  e  is  revealed. 
For  simplicity,  assume  that  the  firm  has  a  constant  proportions 
production  function  calling  for  labor  L  and  capital  K  inputs  given  by 

L  =  aQ  (3a) 

and 

K  =  bQ.  (3b) 

It  is  assumed  that  capital  is  exhausted  in  the  production  process. 
The  net  cashflow  of  the  firm  after  paying  the  wage  rate  w  on  L 
units  of  labor  is  given  by 


-5- 


Y  =  PQ(l+e)  -  wL.  (4) 

Note  that  we  assume  that  the  wage  rate  w  is  deterministic  and  paid  at 

end  of  the  period  when  output  is  sold.   According  to  the  cashflow 

version  of  the  CAPM  the  value  of  the  firm  V  is  the  present  value  of 

the  net  cashflow  given  by 

E(Y)  -  A  cov(Y,R  ) 
v= r— = =-  (5) 


where  A  is  the  market  price  of  systematic  risk,  s    is  the  covariance 

em 

of  e  with  the  market  portfolio,  R  is  tne  uncertain  rate  of  return  on 

m 

the  market  portfolio,  and  r  is  the  risk  free  rate  of  interest.   If  we 

define  4  =  E(l+e)  -  As    as  the  certaintv  equivalent  of  (1+e) ,  then 

era 

since  e  has  a  zero  expected  value  tne  certainty  equivalent  price  is 

simply  E(P(l+e))  -  As    =  4>P.   The  value  of  the  firm  simplifies  to 

em 

V  =  W  -  wL  (5') 

1  +  r  K      J 


=  <frP  -  Wa     .  Q 

1  +  r 

Note  that  in  the  normal  case  we  would  expect  firms  to  have  positive 

systematic  risk  so  with  s   >  0  the  certainty  equivalent  term  5  would 

em 

be  less  than  one.   Consequently,  uncertain  revenue  is  valued  at  less 
than  its  expected  value  due  to  the  discount  for  systematic  risk. 

The  goal  of  the  firm  is  to  maximize  its  net  present  value,  i.e., 
the  difference  between  its  market  value  and  its  capital  expenditure, 

NPV  =  V  -  K  (6) 


-6- 

Substituting  the  production  requirenents  for  L  and  K  in  (3)  and  de- 
fining c  =  wa  +  (l+r)b  as  the  constant  marginal  and  average  cost  of 
production  we  have  the  net  present  vaiue  as 

<i>PO  -  cQ 
NPV  =   I   +   r  '  (7) 

The  first  and  second  order  conditions  for  maximizing  (7)  are 
3 NPV   (i(l-u)P  -  c 


3Q       1  +  r 


=  0  (8) 


and 


3  NPV    6(l-u)    dP 

—  =   1  +  r   '  dQ  <  °  (9) 

3Q 

respectively.   Downward  sloping  demand  is  sufficient  to  assure  that 

(9)  holds.   Re-arranging  (3)  we  have 

(fr(i-u)p  =  c  (yJ) 

which   states    that    the   optimum  is    where    the    firm   equates    the    certainty 
equivalent    marginal    revenue   and   marginal    cost.      Thus,    the    firm   sets 
output    such    that    the    certainty    equivalent    price    is 

<J>P   =  ~—  (10a) 

1    -   u 

or  such  that  expected  price  is 

P  =  777 — r  (10b) 

Note  that  9P  is  the  certainty  equivalent  price  and  c  is  average  and 
marginal  cost.   If  the  firm  possesses  market  power  then  u  >  0  and  the 
certainty  equivalent  price  will  be  set  above  marginal  cost  c. 


-7- 

To  see  the  meaning  of  u  under  uncertainty,  we  can  solve  (10)  for 
u  Co  yield  u  =  ($P-c)/<£P.   Thus  u  represents  in  certainty  equivalent 
form  the  spread  between  price  and  marginal  cost  as  a  proportion  of 
price.   In  the  competitive  case,  this  spread  should  be  non-existent 
and  u  would  be  zero.   When  the  firm  possesses  monopoly  power,  a  posi- 
tive spread  would  exist  indicating  a  positive  value  of  u. 

These  equilibrium  relationships  can  be  used  to  express  the  system- 
atic risk  of  the  firm  as  a  function  of  the  firm's  market:  power  u. 

3.   Systematic  Risk 

According  to  the  CAPM,  systematic  risk  is  measured  by  the  relation- 
ship between  the  rate  of  return  on  the  firm's  securities  and  the  rate 
of  return  on  the  market  portfolio.   Define  the  rate  of  return  on  the 
firm  as  R  where 


Then  the  firm's  systematic  risk,  or  g,  is  given  by 

2 
$  =  cov(R,R  )/s~ 

ra   m 

=  cov(Y,R  )/(Vs2)  (11) 

m     m 

where  cov(R,R  )  is  the  covariance  between  the  rates  of  return  on  the 
m 

2 

firm  and  the  market  portfolio  and  s**  is  the  variance  of  the  return  on 

m 

the  market  portfolio.   This  covariance  term  may  be  simplified  to 


cov(Y,R  )  =  PQs 

m       em 

cs 
=  —  •  Q  (12) 


<>(l-u) 


-8- 

from  (10b).   If  we  substitute  (10a)  into  (5'),  then  the  value  of  the 

firm  can  be  written  as 

c 

-  wa 


V  -  '"x  +  r   •  °-  (13) 

Finally,  using  (12)  and  (13)  we  can  express  (11)  as 

i       s 

1  +  r    era       c  .... 

d>      2c-  wa(l-u) 

in 

Equation  (14)  shows  that  8  is  negatively  related  to  market  power  u 
as  S&T  showed  earlier.   The  difficulty  with  this  relationship  is  that 
market  power  as  measured  by  u  is  extremely  difficult  to  observe  from 
publicly  available  data.   To  be  useful,  S&T's  insight  must  be  trans- 
lated into  a  form  that  can  be  estimated  from  market  data. 

C.   Tobin's  q 

Recall  that  Tobin's  q  is  defined  as  the  ratio  of  the  firm's  market 
value  to  the  replacement  cost  of  its  capital  stock.   A  value  of  q 

exceeding  unity  implies  that  a  firm  is  earning  above  a  normal  rate  of 

return  on  its  capital.  To  see  this,  consider  a  firm  that  has  no 

monopoly  power,  i.e.,  u  =  0.   Then  from  (10)  we  see  that  the  optimum 

calls  for  6p  =  c,  i.e.,  the  certainty  equivalent  price  equals  marginal 

cost.   The  value  of  the  firm  in  (13)  is  simply 

V  =  (c-wa)Q/(l+r)  =  bQ 


=  K 


Thus,    Tobin's    q  would   be   1. 


-9- 

In  the  more  general  case,  we  have  ^P(l-u)  =  c  at  the  optimum 
yielding 

q  =  V/K 

-  1  +  nLh  •  t^—  •  <15) 

(H-r;b   1  -  u 

Thus,  for  u  >  0  we  see  that  q  >  1.   Furthermore,  q  is  positively  re- 
lated to  u.   Being  able  to  estimate  q  obviates  the  difficulties  asso- 
ciated with  trying  to  estimate  u. 

If  we  solve  (15)  for  u  as  a  function  of  q  we  get 

u   -  q   '   '  (16) 

wa 

TlTrTb   +  q 
which    can    be    substituted    into    (14)    to   give 
1    +   r    •    Spti         r  -,  wa  1 


_em 

s 


s-^      2"  !i+TT^Tb-f)  <17> 


m 

Here  it  can  be  seen  that  0  is  negatively  related  to  q.   That  is,  there 

is  a  one-to-one  positive  relationship  between  u  and  q,  and  since  3  and 

u  are  negatively  related,  then  0  and  q  will  also  be  negatively  related. 

In  fact,  we  can  compare  this  general  result  to  the  special  case  of 

the  competitive  firm  for  which  u  =  0  and,  therefore,  q  =  1.   In  that 

case,  the  systematic  risk  3   is  given  by 

c 

s 
1  +  r    era   ,      wa 

6c=~ r-u  +  o^-  (18) 

v     s 

m 

Finally,  we  can  write  the  systematic  risk,  of  the  non-competitive  firm 
as 


-10- 
1  +  r    era  •    wa      , .    1 ,  . ,  _ . 

&'*c-— r    or?)b-[i-7!-  (19) 

s 
m 

The  departure  of  (3  from  3   is  negative  and  tlie  spread  increases  in 

c 

absolute  magnitude  with  the  size  of  q. 

The  expression  for  8  in  (17)  shows  that  systematic  risk,  is  depen- 
dent on  both  q  and  s   among  other  variables.   The  first  of  these  re- 
em 

lationships  shows  that  6  is  negatively  related  to  q.   Thus,  a  firm 
that  has  market  power  as  measured  by  q  will,  ceteris  paribus,  have 
lower  systematic  risk.   The  second  relationship  snows  that  3  is  posi- 
tively associated  with  s   .   Note  that  s    shows  the  covariance  of 

em  era 

the  stochastic  demand  term  with  the  return  on  the  market  portfolio. 
Thus,  if  the  firm's  stochastic  demand  is  highly  correlated  with  the 
demand  for  the  output  of  other  firms  in  the  market  portfolio,  then  the 
firm's  systematic  risk  will,  ceteris  paribus,  be  higher.   In  other 
words,  firms  with  product  demands  that  are  highly  correlated  with 
sales  of  other  firms  in  the  economy  will  have  higher  6's  and  higher 
risk  preraia  in  the  CAPM  context. 

Our  model  indicates  that  systematic  risk  as  measured  by  3  should 
be  negatively  related  to  market  power  and  positively  related  to  the 
covariance  of  the  firm's  sales  with  the  rest  of  the  economy.   To  test 
these  hypotheses  requires  that  (17)  be  arranged  into  a  more  convenient 
form  that  can  be  estimated  from  available  public  data. 

U.   Estimable  Forms 

The  difficulty  with  (19)  in  its  current  form  is  that  s   ,  or  the 

em 

covariance  of  price  with  the  market  portfolio,  is  not  directly 


-11- 

observable.   Using  aggregate  sales  revenue  for  Che  firm  will  overcome 
this  problem.   That  is,  re-write  (12)  as 


Cov(Y,R  )  =  Cov(PQ(l+e),R  ) 
rn  m 


=  Cov(S,R  )  (20) 

m 


where  S  is  the  uncertain  total  revenue  or  dollar  volume  of  total 
sales.   Then  from  the  definition  of  c  we  can  express  the  value  of  the 
firm  in  (13)  as 


C  •      11 


=  'TI^'r^I  +  lllc  (21) 

where  bQ  is  the  capital  requirement  in  (3b).   Then  if  we  substitute 

(20)  and  (21)  into  (11)  we  have  systematic  risk  expressed  as 

Cov(S,R  ) 
8  = a (22) 

[1  +-^—  •  -^-JKs2 
(l+r)b   1  -  u   m 

Finally,  we  can  substitute  for  u  in  terms  of  q  from  (16)  to  give 

0=1-.  Cov(|,  R  )  •  -.  (23) 

2        K   21     q 
s 
m 

Here,  the  ratio  S/K  is  the  capital  turnover  ratio  or  the  sales  revenues 
generated  per  dollar  of  investment  in  capital.   This  is  commonly  re- 
ferred to  as  the  "asset  turnover  ratio." 

The  final  difficulty  in  estimating  the  model  is  that  the  system- 
atic risk  in  (23)  is  a  "firm"  3.   Unfortunately,  most  major  corporations 


-12- 

have  both  debt  and  equity  outstanding  so  there  is  no  single  security 
that  allows  us  to  estimate  the  overall  firm  3.   Instead,  we  are  left 
with  estimating  the  0  for  a  security  instead  of  the  entire  firm. 
Specifically,  we  estimate  the  3  for  the  equity  of  the  firm  which  re- 
flects both  overall  firm  risk  and  the  additional  effects  of  financial 
leverage.   To  account  for  the  effect  of  deot  usage  on  the  equity  3  of 
the  firm  we  make  an  adjustment  developed  by  Hamada  [1972]. 

Denote  the  total  value  of  the  firm  as  the  sum  of  the  values  of  the 
outstanding  securities 

V  =  V  +  V,.  (24) 

3     L 

where  V   and  V   are  the  respective  values  of  the  bonds  and  the  equity 
B       E 

securities.   Then  as  Hamada  shows,  the  3  for  the  equity  can  be  ex- 
pressed as 

3£  -  B("VJL).  (25) 

£ 

In  other  words,  the  3  for  a  levered  firm's  equity  is  the  overall  firm 

3  multiplied  by  the  ratio  of  firm  value  to  equity  value. 

Finally,  we  can  express  the  equity  3  as 

1  S   ~      1  VR 

g^  -A-  •  Cov(£,  R)  .  -  .  (1  +-£).  (26) 

E     2       K   m    q        V_ 
s  n         E 

m 

S 
The  first  firm-specific  term,  Cov(— ,  R  ),  represents  the  systematic 

K.        m 

"business    risk"    of    the   firm  as    measured    by    the    relationship    of    the 
firm's    capital    turnover   in   relationship    to    the    rest    of    the   market 
portfolio.      The   second    terra,    1/q,    is    the    inverse   of    the   firm's    market 


-13- 

power  as  measured  by  Tobin's  q.   The  final  term,  V'/V  ,  reflects  Che 
capital  structure  or  leverage  of  the  firm.   This  multiplicative  rela- 
tionship indicates  that  the  firm's  systematic  risk,  is  positively  re- 
lated to  business  risk  and  leverage  and  negatively  related  to  the 
firm's  market  power. 

Furthermore,  as  noted  by  Bowman  [1980],  the  risk  class  concept  of 
Modigliani  and  Miller  [1958]  points  to  the  possibility  of  differential 
business  risk  across  industries.   That  is,  a  portion  of  beta  could  be 
explained  by  the  use  of  intercept  dummy  variables  (D).   In  the  context 
of  multiple  regression  analysis,  the  intercept  dummy  variables  based 
upon  industries  will  capture  that  portion  of  beta  whicn  varies  system- 
atically between  industries.   Thus,  the  model  at  this  point  can  be 
stated  functionally  as: 

S  -  VR 

6£  =  f(Cov(~,  Rm),  q,  ^,  D). 

III.   Sample  Selection  and  Measurement  of  Variables 

Because  of  the  technical  problem  involved  in  the  measurement  of 
Tobin's  q,  firms  comprising  the  1978  Standard  and  Poor's  400  provide  the 
initial  sample  for  our  empirical  analysis.   Then,  data  availability 
criteria  are  imposed  to  ensure  continuous  data  on  the  COMPUSTAT  and 
CRSP  tapes  for  the  period  from  1969  to  1978.   The  remaining  116  firms 
are  then  classified  according  to  their  two-digit  Standard  Industry 
Classification  (SIC)  Code.   Because  of  the  use  of  dummy  variables  in 
the  model,  the  inclusion  of  firms  from  industries  with  only  a  small 
number  of  firms  is  insufficient.   In  an  attempt  to  preserve  high 


-14- 

degrees  of  freedom,  the  seven  largest  industry  groups  are  chosen.   This 
gives  a  sample  of  94  firms  distributed  according  to  SIC  Code  as  shown 
in  Table  1. 


Insert  Table  1 


In  what  follows  we  address  the  measurement  issues.   First,  beta 
defined  by  the  CAPM  is  not  directly  observable.   The  market  model  is 
commonly  used  empirically  to  obtain  a  surrogate.   We  employ  120  monthly 
excess  returns  in  the  market  model  so  chat  the  nonstationari ty  problem 
of  beta  is  reduced  to  a  minimum. 

The  systematic  business  risK.  variable  COV  is  the  covariance 
between  capital  turnover  ratio  and  annual  return  on  the  mark.ec  port- 
folio.  This  variable  is  very  similar  to  the  accounting  beCa  used  in 
the  literature. 

The  firm's  q  ratio,  it  is  recalled,  is  the  ratio  of  the  firm' 
market  value  to  the  replacement  cost  of  its  assets.   The  estimation  of 
q  is  similar  to  procedures  described  in  Lindenberg  and  Ross  [1981 j  and 
Chappell  and  Cheng  [1982,  1984].   It  includes  adjustments  for  the 
baises  induced  by  inflation  in  the  reported  values  of  property,  plant 
and  equipment,  and  inventories  and  by  interest  rate  changes  in  the 
reported  value  of  debt.   Details  of  the  estimation  procedure  are  avail- 
able from  the  authors.   For  the  firms  in  our  sample,  we  have  averaged 
q  ratios  for  the  period  from  1969  to  1978. 

vB 

As  shown  in  section  II,  the  leverage  variable  -rr~  is  measured  as 
the  ratio  of  market  value  of  debt  to  market  value  of  common  equity. 
Since  the  book  value  measure  of  leverage  has  been  intensively  used  in 


-15- 

the  literature,  both  market  value  and  book  value  measures  (LM  and  LB) 
are  tested.  In  order  to  obtain  a  stable  measure,  we  average  the  debt 
to  equity  ratio  over  the  ten  year  period. 

IV.   Hypothesis  and  Empirical  Results 

As  shown  in  section  II  of  this  paper,  market  power  as  measured  by 
Tobin's  q  is  theoretically  negatively  correlated  with  beta.   Kence , 
the  primary  null  hypothesis  is: 


H,-> :   Market  power  as  measured  by  Tobin's  q  is  not 
statistically  correlated  with  market  beta. 


A  multiple  regression  analysis  of  the  full  model  presented  in  (26) 
constitutes  the  principal  test  of  the  null  hypothesis.   Since  all  three 
variables,  COV ,  q,  and  LM  (or  LB)  are  in  a  multiplicative  relationship 
with  3„,  we  take  natural  logarithms  on  all  variables  and  add  industrv 
dummy  variables  in  the  following  multiple  regressions: 

6 

In  0„  =  an  +  a.  In  COV  +  a~  In  LM  +  a,  In  q  +  Z      a.x,D.  +  e    (27) 
L     0    1  2  3  l+J  l 

i=l 

where  a,  and  a2  are  hypothesized  to  be  positive  and  a-,  negative.   The 
significance  of  cc.  is  a  direct  test  of  the  null  hypothesis. 

To  investigate  the  hypothesized  relationship  further,  we  first  exa- 
mine the  correlation  matrix  for  the  variables  used  as  shown  in  Table  2. 
It  is  found  that  there  is  a  problem  of  raulticollineari ty  between  market 

power  and  leverage  measures,  with  a  correlation  coefficient  of  -0.526. 

2 
This  finding  has  been  documented  in  industrial  organization  studies." 


Insert  Table  2 


-16- 

Furthermore,  examination  of  the  latent  vectors  and  roots  of  Che 
nine  independent  variables  in  equation  (27),  which  are  presented  in 
Table  3,  indicates  more  precisely  that  these  variables  are  highly 
correlated  and  that  the  market  power  and  leverage  variables  are  the 
main  sources  of  multicollinearity .   Because  the  presence  or    multi- 
collinearities  in  a  data  base  generally  inflates  ordinary  least  squares 
(OLS)  estimator  variances,  the  OLS  estimates  are  very  unstable,  even 
though  unbiased. 

The  principal  component  regression  (PCR)  technique   is  used  to 
alleviate  the  problem  of  multicollinearity.   Gunst  and  Mason  [198UJ 
show  that  principal  component  coefficient  estimates  eliminate  raulti- 
collineari ties  from  the  OLS  estimators,  thereby  greatly  reducing  esti- 
mator variance  while  attempting  to  introduce  only  a  small  amount  or 
bias.   Principal  component  estimates  are  biased,  but  more  stable  with 
smaller  variances  than  the  OLS  estimate.   We  first  transform  the  inde- 
pendent variables  into  an  equal  number  of  components  that  are  linear 
combinations  of  the  independent  variables  and  then  eliminate  the  com- 
ponents associated  with  very  small  (near  zero)  latent  roots.   The 
critical  value  (the  small  cutting-off  value)  for  the  latent  roots 

should  be  large  enough  to  eliminate  multicollinearity,  yet  small  enough 

4 
to  minimize  the  bias  resulting  from  the  omitted  components. 

The  PCR  results  of  equation  (27J  are  shown  in  Table  4.    The  coef- 
ficient  of  the  market  power  variable,  a~,  is  negative  and  significant 
at  5  percent  level.    Therefore,  the  null  hypothesis  is  rejected. 
Market  power  as  measured  by  Tobin's  q  indeed  is  statistically  corre- 
lated with  market  beta.   This  finding  is  important  in  the  sense  that  it 


-17- 

supports  Sullivan  [1973,  1982]  in  that  market  power  reduces  a  firm's 
systematic  risk  and  thus  its  cost  of  equity  capital.   Most  importantly, 
this  result  supports  the  hypothesis  testing  derived  from  an  integrated 
theoretical  model,  which  was  absent  in  Sullivan  and  Curley,  et .  al . 

Furthermore,  our  results  confirm  the  existence  of  other  variables 
in  addition  to  market  power  as  determinants  of  systematic  risk.   First, 
the  coefficient  of  the  systematic  business  risk  term  is  positive 
although  not  statistically  significant.   Second,  the  leverage  variable 
is  positive  and  significant  at  the  1%   level,  a  result  consistent  with 
earlier  findings  in  the  finance  literature.   Finally,  the  industry 
dummy  variables  play  a  significant  role  in  explaining  inter-industry 
differences  in  betas.   In  fact,  the  industry  dummy  variables  may  pick 
up  systematic  risk  differences  between  industries  more  effectively  than 
the  business  risk  term,  COV.   Nevertheless,  firm-specific  variables 
explain  a  significant  portion  of  individual  firm  betas. 


Insert  Table  3 


Insert  Table  4 


VI.   Summary 

In  this  paper  we  investigate  the  relationship  between  a  firm's  sys- 
tematic risk  and  it's  market  power  as  measured  by  Tobin's  q,  the  ratio 
of  market  value  to  replacement  cost  of  the  capital  stock.   Starting 
from  the    earlier  theoretical  work  of  Subrahmanyam  and  Thomadakis 
[ 1 980 J  ,  we  develop  a  testable  model  relating  the  firm's  beta  to  its 
q-ratio.   Our  model  predicts  and  our  empirical  results  confirms  that 


-18- 

beta  is  positively  related  to  business  risk  as  measured  by  the  sensi- 
tivity of  firm  sales  to  aggregate  economy  sales,  positively  related  Co 
financial  leverage  as  measured  by  debt-equity  ratios,  and  negatively 
related  to  market  power  as  measured  by  Tobin's  q. 

Our  results  would  seem  to  have  several  implications  for  the  study 
of  industry  structure  and  performance.   First,  it  is  important  to  under- 
stand the  underlying  cause  of  the  relationship  between  systematic  risk 
and  market  power.   Note  that  by  virtue  of  using  the  capital  asset 
pricing  model  as  the  description  of  the  underlying  security  market 
equilibrium  we  are  assuming  that  the  firm  is  a  price-tatcer  in  the  capi- 
tal market.   In  other  words,  the  existence  of  market  power  in  the  pro- 
duct market  in  no  way  produces  market  power  in  the  securities  market. 
The  lower  systematic  risk  and  resultant  lower  cost  of  equity  capital, 
ceteris  paribus,  for  a  firm  with  a  q-ratio  in  excess  of  unity  arises 
because  it  generates  higher  expected  dollar  returns  per  unit  of  product 
price  risk,  s   ,  and  not  from  any  non-competitive  access  to  the  capital 
market.   Thus,  it  is  the  higher  expected  return  per  unit  risk  that  pro- 
duces a  lower  beta  and  a  lower  cost  of  equity  capital. 

Second,  it  should  be  noted  that  assuming  that  there  exists  a  common 
cost  of  capital  for  an  entire  industry  is  not  appropriate  even  as  an 
approximation.   While  our  empirical  results  indicate  that  there  is  a 
strong  industry  effect,  or  "business  risk"  component  in  beta,  it  can 
also  be  seen  that  individual  firm  variables,  in  particular  leverage  and 
market  power,  have  significant  influences  on  individual  firm  betas. 
Thus,  there  is  good  reason  to  believe  that  assigning  a  single  "industry 
beta"  to  individual  firms  within  an  industry  will  obscure  important 
cross-sectional  differences  between  firms. 


-19- 

Footnotes 
1 
"For  example,  see  Curley,  Hexter,  and  Choi  [1982]. 


See  Tobin  and  Brainard  [1968,  1977]  and  Tobin  [1969,  1978]. 
2. 


3 
The  critical  value  for  the  latent  roots  in  the  PCR  is  0.2. 

4 
For  more  detailed  information  on  principal  component  regression 

analysis,  see  Mansfield,  Webster,  and  Gunst  [1977],  and  Gunst  and 

Mason  [1980]. 

Because  the  PCR  results  with  book  value  leverage  measure,  LB,  are 
analogous,  we  do  not  report  them  here. 

We  also  include  two  ad  hoc  variables  in  the  test,  growth  (the 
geometric  mean  annual  rate  of  growth  in  sales  from  1969  through  1978) 
and  size  (1978  sales  in  natural  logarithm).   The  coefficient  of  the 
market  power  variable  is  still  negative  and  significant  at  10  percent 
level. 


-20- 


Ref erences 


1.  Bowman,  R.  G.  ,  "The  Debt  Equivalence  of  Leases:   An  Empirical 
Investigation,"  The  Accounting  Review  (April  1980),  237-253. 

2.  Chappell,  H.  W. ,  Jr.  and  D.  C.  Cheng,  "Expectations,  Tobin's  q, 
and  Investment:   A  Note,"  Journal  of  Finance  (March  1982), 
231-236. 

3.  ,  "Firm's  Acquisition  Decisions  and  Tobin's  q  Ratio," 

Journal  of  Economics  and  Business  (February  1984),  29-42. 

4.  Curley,  A.  J.,  J.  L.  Hexter,  and  D.  Choi,  "The  Cost  of  Capital  and 
the  Market  Power  of  Firms:   A  Comment,"  Review  of  Economics  and 
Statistics  (August  1982),  519-523. 

5.  Gunst,  R.  and  R.  Mason,  Regression  Analysis  and  Its  Application: 
A  Data-Oriented  Approach  (New  York:   Marcel  Dekker,  Inc.,  1980). 

6.  Hamada,  R. ,  "The  Effect  of  the  Firm's  Capital  Structure  on  the 
Systematic  Risk  of  Common  Stocks,"  Journal  of  Finance  (May  1972), 
435-452. 

7.  Hite,  G.  L.,  "Leverage,  Output  Effects,  and  the  M-M  Theorems," 
Journal  of  Financial  Economics  (March  1977),  177-202. 

8.  Hurdle,  G.  J.,  "Leverage,  Risk,  Market  Structure  and  Profitability, 
Review  of  Economics  and  Statistics  (November  1974),  478-485. 

9.  Lindenberg,  E.  and  S.  Ross,  "Tobin's  q  Ratio  and  Industrial 
Organization,"  Journal  of  Business  (January  1981),  1-32. 

10.  Lintner,  J.,  "The  Valuation  of  Risky  Assets  and  the  Selection  of 
Risky  Investments  in  Stock  Portfolios  and  Capital  Budgets,"  Review 
of  Economics  and  Statistics  (February  1965),  13-37. 

11.  Mansfield,  E.  R. ,  J.  T.  Webster,  and  R.  F.  Gunst,  "An  Analytic 
Variable  Selection  Technique  for  Principal  Component  Regression," 
The  Journal  of  the  Royal  Statistical  Society  (Volume  26,  No.  1, 
1977),  34-40. 

12.  Melicher,  R.  W. ,  D.  F.  Rush  and  0.  N.  Winn,  "Degree  of  Industry 
Concentration  and  Market  Risk-Return  Performance,"  Journal  of 
Financial  and  Quantitative  Analysis  (November  1976),  627-635. 

13.  Modigliani,  F.  and  M.  Miller,  "The  Cost  of  Capital,  Corporation 
Finance  and  the  Theory  of  Investment,"  American  Economic  Review 
(June  1958)  ,  261-297.' 

14.  Mossin,  J.,  "Equilibrium  in  a  Capital  Asset  Market,"  Econometrica 
(October  1966),  768-784. 


-21- 


15.  Sharpe ,  W. ,  "Capital  Asset  Price:   A  Theory  of  Market  Equilibrium 
Under  Conditions  of  Risk,"  Journal  of  Finance  (September  1964), 
425-442. 

16.  Subrahmanyam,  M.  and  S.  Thomadakis ,  "Systematic  Risk  and  the  Theory 
of  the  Firm,"  Quarterly  Journal  of  Economics  (May  1980),  437-^51. 

17.  Sullivan,  T.  G. ,  "The  Cost  of  Capital  and  the  Market  Power  of 
Firms,"  Review  of  Economics  and  Statistics  (February  1977),  108-113. 

18.  ,  "The  Cost  of  Capital  and  the  Market  Power  of  Firms: 

Reply  and  Correction,"  Review  of  Economics  and  Statistics 
(August  1982),  523-525. 

19.  Thomadakis,  S.  3.,  "A  Model  of  Market  Power,  Valuation  and  the 
Firm's  Return,"  Bell  Journal  of  Economics  and  Management  Science 
(Spring  1976),  150-162. 

20.  Tobin,  J.,  "A  General  Eauilibrium  Approach  to  Monetary  Theory," 
Journal  of  Money,  Credit  and  Banking;  (February  1969),  15-29. 

21.  ,  "Monetary  Policies  and  the  Economy:   the  Transmission 

Mechanism,"  Southern  Economic  Journal  (April  1978),  421-431. 

22.  ,  and  W.  Brainard ,  "Pitfalls  in  Financial  Model  Building, 

American  Economic  Review  (May  1968),  99-122. 

23.  ,  and  ,  "Asset  Markets  and  the  Cost  of  Capital," 

in  B.  Belassa  and  R.  Nelson  (eds.),  Economic  Progress  Private 

Values  and  Public  Policies:  Essays  in  Honor  of  William  Fellner 

(Amsterdam:   North-Holland,  1977). 


D/21 


Table  1 

Firms  Distribution  by  SIC  Code 

2-Digit 

SIC  Code           Industry  Description  Firr.s 

20                Manufacturing-Food  15 

28  Apparel  and  other  Finished  Products  11 

29  Petroleum  Refining  3 

35  Manufacturing-Machinery  30 

36  Electrical  &  Electronic  Machinery  3 

37  Transportation  Equipment  14 

38  Measuring  and  Analyzing  Instruments 

94 


Table  2 

Correlation  Matrix 

P£      COV     LB  LM       q 

6E          1.000    0.234   0.273  0.282   -0.031 

COV                  1.000   0.251  0.095   -0.220 

LB                         1.000  0.594   -0.414 

LM  1.000   -0.526 

q  1.000 


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