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保險業集中度及效率對市場競爭程度的影響：以日本產險業為例
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acquisitions in addition to regulatory changes since 1996, which provides the perfect
research environment for us to examine the potential factors affecting market competition.
Third, our study effectively controls for the influence of government regulation given that
the Japanese nonlife insurance industry is subject to a uniform regulatory environment. We
believe the results of our study can provide appropriate suggestions to countries similar in
this way to Japan, such as Taiwan. Fourth, past research uses factors such as product price to
examine theories such as the structure-conduct-performance (SCP) paradigm or the
efficiency hypothesis. By applying the Lerner index in the evaluation of the market
competition level, we complement the literature by reexamining traditional theories. Finally,
this study has implications for insurance company strategy. Specifically, firms should tailor
their product composition or risk-taking behaviors to specific types of market competition.
2. Data and Methodology
We examine the Japanese non-life-insurance industry from 2001 to 2012. Our sample
data is unbalanced panel data consisting of 313 observations. Of these observations, 18 were
missing variables such as capital price, and the omission of output price in a further 12
observations reduced the final sample to 283 for calculating profit efficiency. The main
regression model (model [1]) is
LI
it
=
α
1
HHI
t
+
α
2
EFF
it
+
α
3
ln
TA
it
+
α
4
(ln
TA
it
)
2
+
α
5
DIV
it
+
α
6
MS
it
+
α
7
AUTO
it
+
α
8
Leverage
it
+
α
9
GDP
it
+
μ
it
+
ε
it
(1)
where i refers to the i
th
firm and t refers to the t
th
year. The remaining terms in the model
are defined as follows.
LI:
Lerner Index variable
HHI:
Herfindahl-Hirschman index
EFF:
efficiency measure of the insurer, including technical efficiency (TE) and
profit efficiency (PE) measures
lnTA:
natural logarithm of total assets
(LnTA)
2
: square of the natural logarithm of total assets
DIV:
diversification measure
MS:
market share of the insurer
Auto:
percentage of auto line in terms of premium
Leverage: debt-to-equity leverage ratio