The greenback traded 0.3 percent from the lowest in seven weeks versus the yen before Federal Reserve Chair Janet Yellen testifies to U.S.
Whiting Petroleum Corporation on Sunday said it would buy Kodiak Oil & Gas Corporation for $3.8 billion in stock, and assume $2.2 billion of Kodiak's debt.
US stocks managed to score modest gains on Friday, but the S&P 500 posted its biggest weekly drop since April as investors showed only mild enthusiasm after getting their first glimpses of earnings.
Hong Kong stocks rose, with the benchmark index climbing after capping its biggest weekly drop since May, as telecommunications companies jumped.
Prosecutors in Shanghai have indicted the foreign couple behind the private investigation firm that was hired last year by drugmaker GlaxoSmithKline Plc (GSK) in China, the official Xinhua News Agency reported.