Wu founded Taishin International Bank via merger in 1992, divesting from his father's textiles company to do so. In February 2002, Wu's Taishin Financial Holdings began business operations. Months after its establishment, Taishin Financial announced a planned merger with Taiwan Securities Company and. Later that year, Taishin Financial broke ground on a new office building, the Taishin Tower. Wu also explored merging with, held by his brother Eugene. Plans for the merger were called off after days of consideration. In 2003, Taishin Bank launched the Visa Infinite card throughout Asia. The next year, Wu considered a merger with. In March 2004, Wu stated that Taishin Financial had partnered with Test Rite International to securitize Time Plaza, and that the site was the first property-backed securitization project targeting pre-sold housing units. In August 2004, Thomas Wu terminated several Taishin Financial board members close to his brother Eric. Later that month, the board of directors of Shinkong Synthetic Fibers Corporation elected Thomas to serve as company chairman. Their mother made it known that she preferred Eric take the position, and asked Thomas to step down. Eric and his mother contested Thomas's election, because members of the board were to be reselected prior to the vote that installed Thomas as chairman. As the business chairmanship dispute continued, Thomas and Eric were suspected of insider trading and investigated by the Financial Supervisory Commission. In November 2004, the conflict was resolved. Thomas yielded the chairmanship of Shinkong Synthetic Fibers Corporation to Eric, and was named to the same position at Taishin Financial Holdings. In turn, Eric ceded his proxy votes on the Taishin Financial board to Thomas, and secured Taishin Investment Trust Company's independence from Taishin Financial. The FSC ruled in December 2004 that there were no financial gains, and therefore no insider trading, but that Taiwan Securities Company had not sought final approval to trade shares in Shinkong Synthetic Fibers. As a result, Taiwan Securities Company was fined NT$2.5 million. With the leadership dispute resolved, Taishin Financial share price rose to NT$29.40 in early December 2004. Thomas Wu expressed support for the Financial Supervisory Commission as the agency announced criteria for the merger of financial holding companies in December 2004. The next year, Wu began considering plans for merger and acquisition. Wu stated in March 2005 that Bank SinoPac had elected to considered a merger with the International Bank of Taipei instead of Taishin Financial. SinoPac chairman Richard Hong said, "The talks with Taishin did not collapse," and that a final decision would be made in May. Taishin charged two SinoPac employees with libel in May, for distributing an email to SinoPac shareholders including incorrect information regarding Taishin. After SinoPac apologized for the miscommunication, the charges were withdrawn. After the merger with SinoPac fell through, Taishin Financial bid NT$36.6 billion for a controlling stake in Chang Hwa Commercial Bank. In December 2005, Taishin Financial sought to acquire a larger share of Chang Hwa. By October 2006, the financial institutions were proposing a share swap. Taishin Financial and Aegon N.V. formed a joint venture in insurance in June 2007. The deal also included a 2.5% stake of Chang Hwa changing hands. Wu announced in July that the merger between Chang Hwa and Taishin Financial would be complete by the end of the year. However, the Executive Yuan stalled the merger, necessitating the sale of Taishin Securities Company to the Koos Group. A Taishin Financial shareholders' meeting in June 2013 saw the passage of a resolution permitting Wu to pursue legal action to merge Taishin International Bank and Chang Hwa Bank. Days later, Chang Hwa executives also formally backed the merger.
