Japan's yen has been weakening against the U.S. dollar despite the Bank of Japan ending its negative interest rate policy. The recent yen weakness is attributed to Japan Inc.'s reluctance to repatriate profits, leading to less yen buying during Tokyo trading hours. The top currency official reaffirms readiness to intervene if needed to prevent excessive exchange rate swings. The BOJ's rate hike has widened the yield gap with the U.S. and Europe, further causing the yen to slide. Investors in Japan's government bonds may face potential interest-rate hikes and a reduction in the central bank's bond holdings.