More evidence of a so-called duopoly coming into play as Expedia and Booking.com land 80% of all European hotel sales on online travel agencies.
European hospitality association HOTREC estimates the pair have increased their dominance of the marketplace as the third semi-major player on the continent, HRS, has "lost ground significantly" in recent years.
Still, the trio accounted for 92% of all OTA bookings in 2015, HOTREC says.
The organisation says the OTA sector covers around 200,000 properties in Europe, with around three-quarters being small, independently owned, so having two major players shows "there is no need for further explanation on who is in the driving seat".
Some 2,000 of HOTREC's members took part in a recent study, with a key finding showing that almost one in four of their collective room being are generated through OTAs during 2015.
Priceline Group-owned Booking.com took 60% of the market.
HOTREC says its hotel members have not experienced any increased competition between OTAs, despite such a trend expected to emerge as the marketplace moved to apparent "narrow parity clauses" following high-profile regulatory changes in various countries.
In addition, there has not been any significant movement (such as a decrease) in commission levels paid by hotels to OTAs.
Overall, HOTREC found, direct bookings fell to a 55% share of all room night sales during 2015.
Chair of the organisation's distribution task force, Markus Luthe, says:
"It is crucial that despite the huge imbalance between the various players the market conditions become more fair and balanced, with the freedom of each and every single hotelier to be able to set their own conditions for their own services freely and be able to fairly negotiate on contract terms and conditions with every distribution partner."
CEO Christian de Barrin says the OTA market is moving towards a "duopolistic one in Europe", with him even suggesting an overall monopoly by Booking.com given its almost two-thirds market share.
Regarding commission levels, just 8.5% of hoteliers reported a reduction in commission levels in the last 12 months.
The report adds:
"Among the few ones having received any reduction, big and chain hotels were significantly overrepresented, compared to the small and individual hotels."
UPDATE: ETTSA, the OTA lobby in Europe, has responded.
NB:Monopoly hotel image via BigStock.