A yen surge in New York late Wednesday fueled speculation that Japanese authorities intervened for a second time this week, before the currency began to weaken again in Tokyo trading, paring much of the move.

The yen advanced more than 3% and hit ¥153.04 per dollar as more than $4 billion of yen-related futures were exchanged in the final stretch of the U.S. trading session. That was the largest number of contracts since Feb. 2, according to volumes data recorded by CME. Japan’s currency then weakened more than 1% in Asia trading on Thursday to around the ¥156.10 level.

"It would certainly appear to have the characteristics of an intervention,” said Nathan Thooft, global chief investment officer for the multiasset solutions team and senior portfolio manager for Manulife Investment Management. "Repeated attempts certainly send a message to the market and while it may not fully hold, it should have some impact on preventing further meaningful weakness.”