Here are some numbers to grab your attention and ponder: The U.S. dollar has rallied almost 25% percent in the past nine months and 35% over the past four years. In light of these substantial and notable gains by the bullish greenback, it’s hard not to ask: What is propelling the dollar’s surge? What should investors do going forward? Will the big dollar rally continue?

The answer to the last question is an emphatic yes. As Alan Ruskin, Managing Director and Global Co-Head of FX Research at Deutsche Bank, observed in a recent conference call, the dollar is expected to gain another 20% against the euro and 10% against the yen by 2017. That would mean the dollar will equal 0.85 euro in two years and the dollar will reach a value of 130 yen in that same time frame. (It’s worth noting that the euro projections assume no Greek exit—if Greek were to leave the euro, it would likely add another 10% decline against the dollar.) The recent pull back in the dollar is deemed to be temporary (this is normal, and there have been five pull backs since the 2011 dollar rally commenced). The dollar is expected to peak in 2017, following a 2011-2017 dollar cycle that would mirror past major multi-year currency moves from 1978-1985 and 1995-2002.

Why the big dollar move? Ruskin emphasized three reasons: (1) continued negative interest rates set by the European Central Bank, (2) easing of interest rates by the Bank of Japan and, (3) most importantly, expected higher interest rates from the U.S. Federal Reserve compared to other G10 countries. In other words, the rate differential between the U.S. and other G10 countries will widen, making the dollar more attractive. To reach 0.85 euro, the bank assumes the Fed funds rate will reach 200 basis points (up from the current 25 basis points). Conversely, the biggest threat to the dollar rally is a scenario wherein the Fed does not tighten monetary policy.

So what should investors consider doing with this information? According to Ruskin, hedging currency risk in investment portfolios with such exposure makes sense to protect returns.