Fixed-income investment in a low interest-rate environment From an investment perspective, it seems to me that a low interest-rate environment can yield to some relatively "un-risky" profits.

As the interest-rate can barely go lower, we now it should rise again at some point (take for instance the recent interest-rate hike in the US).

In this case, what would be the corresponding investment vehicle/product to invest in? My guess would be to just short-sell positions in bonds, as an interest-rate rise corresponds to a decrease of bond prices, but this seems too obvious.

Am I missing something, for instance that short-selling of bonds is not permitted?
Your assumption that low interest rates will "eventually" have to rise is not warranted.

Indeed, we are currently witnessing prolonged periods of low interest rates that do not obviously seem to be coming to an end.

Example 1. For 7 years, the US FOMC's target federal funds range remained unchanged at 0–0.25% (from Dec 2008 through Dec 2015). From Dec 2015 through Oct 2018, there have been 8 increases so that it is now 2.00-2.25%. But even after 8 increases, this rate range remains historically low.

Example 2. A more dramatic example is the case of Japan, where the 10-year government bond yield has remained closed to 0% for two decades now (and indeed is under 0% now).

You predict that since interest rates are so low now, they must rise. You might very well turn out to be correct, but this is hardly a certainty and there are many others taking the opposite bet.