Japan’s first interest rate hike in 17 years has failed to deliver the boost to the yen that policymakers had hoped for, with strategists pointing to four key reasons for the currency to remain weak for now.

At the top of the list is rates in Japan that remain much lower than the rest of the world, followed by speculation the yen hasn’t weakened fast enough to invite intervention, low market volatility that favors carry trades, and signs the depreciating currency isn’t bolstering exports.

While officials have said the yen isn’t moving in line with fundamentals, and that they will take appropriate steps to stem declines, the currency remains near the three-decade low of ¥151.97 to the dollar set last week.