Right now there is little to no danger the Federal Reserve will enact a negative interest rate policy (NIRP). Still some experts have called for it and in February Fed Chairwoman, Janet Yellen, noted that although there may be legal issues with lowering rates below zero, the central bank could do it if it so desired.With negative rates already in place in Europe and in Japan, understanding the impact of subzero rates on investors is only prudent.Related: GOLD BUYERS GET SKITTISH AHEAD OF FED RETREATThe Effect Of NIRPThe idea behind negative interest rates is that it would force banks who often park their cash with the Federal Reserve to loan it instead. This would boost the economy through both ready availability of money and low interest rates.In Europe, which has been testing negative rates since 2014, however, this is not what has happened. Since then shares of MSCI EMU Index ETF, which tracks stocks of large and mid-cap companies in Europe has dropped nearly 30%.The Confidence ProblemWhile all this is uncharted territory, the leading theory behind why stocks have dropped in value has to do with confidence. The need for negative interest rates translates to fear on the part of consumers and investors.As a result, instead of borrowing and investing, they save – often in the form of cash. There’s been anecdotal evidence that one of the results of negative interest rates – in Japan at least – has been an uptick in the sale of home safes.What To DoAlthough the overall impact of negative interest rates on the stock market and other investments appears to be negative as well, there are some suggestions about favorable places to put assets in the event of a NIRP environment.From a general perspective, negative rates are good for bonds, real estate and utilities. One stock recommended by Forbes for a NIRP environment is Duke Energy Corp. (NYSE:DUKD). Duke’s 4.28% dividends are no match for a high valued tech stock, but in a NIRP environment might be just enough. In REIT world, Simon Property Group Inc. (NYSE:SPGC) is another Forbes recommendation along with Public Storage (NYSE:PSAC), both for strong growth.On the bond side, Forbes suggests iShares 20+ Year Treasury Bond (TLT).Related: BLUE CHIP BLUES AND BLUE CHIP BOOMSLittle Likelihood of NIRP In The U.S.Fortunately, the likelihood of the Federal Reserve enacting a NIRP is not very high. Friday in Jackson Hole, Wyoming Fed officials said negative interest rates were not needed in the U.S. because both the economy and the job market are improving.The more likely outcome in the U.S. – at least in the more immediate future – will be a rate hike. That could come as early as September but is more likely to happen in December, or even early next year, according to many experts.