Taiwanese chipmaker UMC jumped to its daily limit and became the most heavily traded stock in Taiwan, a sharp rebound after a stretch of heavy selling.

• UMC opened higher and quickly locked at limit-up, with buy orders stacking up far beyond what sellers offered.
• Trading volume exploded, making UMC the biggest stock by turnover on the whole Taiwan market.
• The bounce comes right after big institutional investors dumped shares for three straight days, led by foreign funds.
• UMC's board just approved a large overseas convertible bond sale worth up to $1.8 billion.
• The fundraising is read as preparing capacity and cash for the next growth wave in silicon photonics and specialty chipmaking.

Outlook: The stock's direction now hinges on whether foreign investors stop selling and treat the fundraising as an expansion bet rather than dilution.