NEW YORK ( ETF Expert) -- A fellow money manager recently tweeted, "I'm praying for bad econ news so that the Fed will keep buying bonds. I don't know what else to pray for." I felt the writer's pseudo-pain and promptly bit down on my lower lip.After all, think about what we celebrate in the investment universe today. We want the economy to sputter or meander, just so our central bank will push interest rates into the proverbial basement. We're addicted. Last week the U.S. Dow Jones Industrials rallied more than 200 points after learning that, for the third consecutive month, jobs increased by less than 200,000. The 175,000 new jobs in May beat watered down expectations, but job growth still remains far too anemic for the Federal Reserve to rein in its bond-buying program. In other words, rates will likely remain contained and U.S. stocks can continue to rally. Or will they? At least three ETF categories are struggling mightily. And while ongiong rate manipulation might help turn one category back around (i.e., REITs), it isn't going to help the other two segments (i.e., Asia-Pacific and Natural Resources). Let's take a closer look at these three groupings: 1. REIT ETFs. Real estate investment trusts are required to distribute 90% of their taxable income. The certainty of a distribution is attractive to income investors in much the same way that master limitted partnerships (MLPs) attract a legion of loyalists. By the same token, a 30-year fixed mortgage rising from 3.4% to 4%-plus has already hindered refinancing demand and might take a toll on home-buying itself. In turn, REIT ETFs became particularly vulnerable to Fed "tapering talk."