Competition has weakened in several important areas of Ireland's services sector, according to the Competition and Consumer Protection Commission.
The finding is contained in reports published today as part of the CCPC's State of Competition in Ireland programme.
The study is examining the evolution of competition within Ireland's non-financial services sector over a 15-year period, between 2008 and 2022.
The competition watchdog found that "concentration and average markups have risen in Ireland across multiple industries within the services sector, particularly since 2016."
The CCPC said it means that certain industries have businesses "holding increased market power."
The report said as of 2022, "the top four businesses have an average market share of 37%, up 12 percentage points since 2008."
The study said the pattern is not unique, as it mirrors similar trends observed across other advanced economies.
It concluded the trend is most pronounced in more digitally intensive industries such as Information & Communications, such as ICT services, and Professional, Scientific & Technical services, such as accounting and legal services.
The study found that "a small number of businesses now account for a larger share of turnover" in those areas.
It also found that markups decreased in a number of other areas including the Arts, Entertainment & Recreation and Transport & Storage industries.
The CCPC also said that some of the results showed positive trends with younger businesses having "a dynamic impact with a rising share in turnover and productivity improvements".
As well as the analysis of Ireland's non-financial services sector, the competition watchdog has also released reports on barriers to entry and barriers to expansion.
It said the reports are aimed at further examining factors that may influence concentration and wider business dynamism.
"These reports highlight barriers to entry and expansion for businesses," according to the CCPC.
The commissions said the key barriers include "financial capacity, regulatory burdens, knowledge gaps, and legal costs."
"Addressing barriers to entry and expansion can bring significant market benefits. Notably, more than two decades have passed since the CCPC published its proposals on legal reform, yet issues continue to persist in the sector," the report stated.
"This highlights the need for government to prioritise market reform, and we welcome Government commitments under the Action Plan for Competitiveness and Productivity in this area," the CCPC added.
The Chairperson of the Competition and Consumer Protection Commission said competitive markets are "vital for a healthy economy."
Brian McHugh said the CCPC's initial findings "show an increase in concentration and average markups, meaning the promotion of strong competition has never been more important."
"The report acts as a warning about weakening competition in some sectors," Mr McHugh said.
Mr McHugh said the CCPC will use the findings to help the watchdog "focus our activities on areas where increased competition can have the biggest impact."
The competition watchdog concluded that the findings of the study "point to a services sector where competitive pressures are uneven and, in some industries, clearly diminishing."
"The rise in concentration and market power, coupled with reduced churn at the top of many industries, raises concerns about risks to the long-term health of competition," he added.
