Singapore Exchange on Wednesday asked budget carrier Tiger Airways to explain the sharp rise in its share price and surge in trading activity.

Shares of Tiger Airways closed 13.5 percent to S$1.135, with a volume of 53.5 million shares changing hands. This was four times its average daily volume over the last five sessions.

The bulk of the gains came in the last hour of trading, which one dealer said was linked to rumours Singapore Airlines might raise its stake in the beleaguered carrier.

The budget carrier, about one-third owned by the Singapore flag carrier, is currently suspended from operating domestic flights in Australia due to safety concerns.