According to the articles, the Centa-City Index and Centa-City Leading Index showed a 1.33 per cent increase in second-hand property transactions soon after the government imposed a special stamp duty on buyers who sold their flats soon after purchasing them.

The tax, of up to 15 per cent for properties sold within six months, was introduced on November 19 that year.

The columnist wrote that the indices did not reflect the reality of the situation after the new tax was imposed. The writer said Centaline was "cheating" and "manipulating the market".

The articles described the data as "dubious" and said Shih and a City University professor involved in compiling the index were being "evasive".

The writer did not acknowledge the possibility of honest mistakes, or the fact the website carrying the indices clearly stated that they were based on data from three weeks earlier.

"There is no mention of the three weeks' gap in the notation," said Paul Shieh Wing-tai SC, for Centaline.

He said there was no suggestion that the indices were meant to instantaneously reflect the state of the market.

Shieh described the headline on one of the articles as "sensational". He argued that the newspaper could not rely on a defence of fair comment, despite the generous scope that defence offered.

The firms launched the action against the and its then-chief editor Chan King-cheung in February 2011, after requests for an apology and withdrawal of the articles were refused.

The hearing continues today before Mr Justice Azizul Suffiad.