A bitter public fight between former Taiwanese first daughter Chen Hsing-yu and her ex-husband Chao Chien-ming is escalating into a threatened lawsuit over property loans and a children's education fund.

• Chao claims he paid off the loans on the luxury homes in Tainan and Taichung and on his clinic; Chen calls that untrue.
• Chen says those loans are covered by their divorce agreement, so talking about them publicly breaches a confidentiality clause carrying a NT$100 million penalty.
• She is gathering evidence and plans to sue, saying the money trail is too tangled to explain quickly.
• A separate dispute centers on a NT$23 million education fund; Chen says Chao could not explain where the money was invested when their eldest son asked.
• She argues Chao owes more than the original sum, since the fund was invested and Taiwan's popular 0050 index ETF has doubled.

Outlook: Expect a formal legal filing and more disclosures as Chen builds her case.