Article published on the 2008-07-31 Latest update 2008-07-31 12:36 TU
Pojaman Shinawatra and her brother, Bannapot Damapong, were sentenced to three years in jail for what the judge called "serious violations of the law", while her secretary was given a two-year sentence.
All three were released on bail of five million baht (95,300 euros) each, pending an appeal.
Thaksin has always denied any wrongdoing by his family and says the charges are politically motivated.
His party, Thai Rak Thai, was outlawed after a 2006 military coup, and Thaksin was banned from politics for five years.Thaksin returned from exile in March after his political allies in the People's Power Party set up a coalition government.