BEIJING, April 18 (Reuters) - Taiwan chipmaker TSMC said the biggest earthquake in at least 25 years that struck the island on April 3 caused estimated losses of T$3 billion ($92.44 million) to the company in the second quarter.

The quake is also expected to bring a 50-basis point drop to TSMC's second quarter gross margin, it said in a filing to the Taiwan Stock Exchange.

There were no power outages or structural damage to TSMC's fabs, and critical equipment including EUV machines were not affected, it added. ($1 = 32.4530 Taiwan dollars) (Reporting by Ethan Wang, Ella Cao and Ryan Woo; Editing by Andrew Heavens)