Four hotels are suspected of colluding by sharing with each other the non-public room rates they offer to companies.
Singapore's competition watchdog said they discussed and exchanged "confidential, customer-specific, commercially sensitive information".
In doing so, they infringed the Competition Act, the Competition and Consumer Commission of Singapore (CCCS) said yesterday.
The four hotels are Capri by Fraser Changi City Singapore, Village Hotel Changi and Village Hotel Katong, and Crowne Plaza Changi Airport Hotel. These hotels are between a five-and 15-minute drive from Changi Airport.
The information they shared included the percentage discount that corporate customers asked for during confidential negotiations, and the responses of the hotels' sales representatives. CCCS said such information sharing may have reduced competitive pressure on prices.
It has issued a "proposed infringement decision" (PID), in the form of a written statement, to the hotels' owners and operators.
TWO KEY FINDINGS
1 Staff from Capri, Village Hotel Changi and Village Hotel Katong discussed and exchanged commercially sensitive information about hotel rooms for corporate customers .
2 Staff of Capri and Crowne Plaza Changi Airport hotels did the same.
The decision details the facts uncovered by CCCS during its investigations, triggered by its own detection efforts, of the four hotels.
It uncovered two key findings.
One, staff from Capri, Village Hotel Changi and Village Hotel Katong discussed and exchanged commercially sensitive information about hotel rooms for corporate customers between July 3, 2014, and June 30, 2015 .
Separately, staff of Capri and Crowne Plaza Changi Airport hotels did the same between Jan 14, 2014, and June 30, 2015.
The hotels have six weeks to make their representations to CCCS before a final decision is taken. If found guilty, they can be fined up to 10 per cent of their business turnover for each year of infringement, up to a maximum of three years.
Frasers Hospitality, which runs the Capri by Fraser Changi City Singapore, said: "We do not condone any of our employees engaging in such conduct, and we take such matters seriously."
It added that it will study the PID and respond to the CCCS.
A spokesman for Crowne Plaza Changi said the hotel was unable to comment as an investigation is under way, while Village Hotels could not be reached for comment.