The Thai-based consortium had owned 80% of the club but they have now purchased the remaining 20% from fellow shareholders Cronus Sports Management, who were fronted by Indonesian businessman Iman Arif.
Asia Football Investments completed their takeover of Leicester in October 2010.
The financial backing given to the club, which has seen Sven-Goran Eriksson appointed as manager and several Premier League stars arrive on loan at the Walkers Stadium this season, has come from the King Power Group headed by City chairman Vichai Raksriaksorn and vice-chairman Aiyawatt Raksriaksorn.
Aiyawatt has vowed to continue to plough money into the club in a bid to end its seven-year absence from the Premier League.
"We are very pleased to now own 100% of Leicester City Football Club," Aiyawatt said in a statement on the club's official website.
"This year has been a tremendous experience and everyone at the club is already putting the foundations in place for next season.
"I would like to thank the people of Leicester and Leicestershire for welcoming us into their club and for showing us their support.
"We promise to do all we can to improve the club, deliver success and achieve a return to the Premier League."
Source: PA
Source: PA