The Chearavanont family remains the richest in Thailand with wealth of 938 billion baht, followed by the Chirathivats with 663 billion baht, according to Forbes Thailand.
The Chearavanonts are behind Charoen Pokphand (CP) Group, one of the world's largest purveyors of animal feed and livestock.
Forbes Thailand said the Chirathivat family, which controls Central Group, moved up from third position last year.
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Red Bull energy drink tycoon Chalerm Yoovidhya went up from fourth ranking last year to third with 656 billion baht.
Charoen Sirivadhanabhakdi, the owner of Thai Beverage Plc, dropped from second position to fourth with 544 billion baht.
Vichai Srivaddhanaprabha, King Power's chairman and chief executive, remains in fifth place with 162 billion baht.
Forbes Thailand said the wealth of 50 Thai billionaires exceeded 5 trillion baht this year, rising by one-third from last year. Two-thirds of them had increased their wealth - the four richest by nearly 781 billion baht.