Negative interest rates. The term itself seems an oxymoron, but in 2016, it surfaces every time there’s a negative byte of economic data, usually in the context of a question: Will the Federal Reserve set negative interest rates? A few decades ago, the idea would have been unthinkable. But seven years of near-zero rates in the U.S. and the decision by major markets such as the European Union and Japan to move them lower than zero has moved it much closer to the realm of possibility. Fed Chair Janet Yellen was grilled about negative rates during her semi-annual Congressional testimony in February, and the central bank included an evaluation of how well the country’s financial institutions could handle them in its yearly stress tests, the results of which are due before the end of June. In this series, TheStreet examines what negative interest rates would mean for you: how they work, what they would mean for the U.S. economy and how you could adjust your portfolio to make the most of them.