Taiwanese drone maker Thunder Tiger surged to its daily price limit as lawmakers headed into a contentious vote on a new drone bill, a clear win for investors betting on defense spending.

• Thunder Tiger opened high and locked at limit-up, with heavy buy orders still stacked up unfilled.
• The whole drone sector rallied as Taiwan's legislature prepared to fight over the drone regulation bill.
• The company has been building out capacity, setting up a precision systems arm and an aircraft engine joint venture to make one-time-use engines for attack drones.
• Its drone and unmanned boat assembly plant in Chiayi is on track to finish by the end of the year.
• The financials are softer than the stock move suggests: July revenue fell from a year earlier and first-half profit slipped, even though revenue for the year so far is up.

Outlook: The share price now hangs on how the legislature votes, with the sector likely to stay volatile until the bill's fate is settled.