This matrix of government bond yields is astounding. All the bonds in red have a negative nominal yield. These are indeed very interesting times.
And here's some related commentary from the credit rating agency Fitch:
"Investors' flight to safe assets following the UK's EU referendum on June 23 pushed the global total of sovereign debt with negative yields to $11.7 trillion as of June 27, up $1.3 trillion from the end-May total, according to new analysis by Fitch Ratings. Brexit-related concerns drove more long-dated bond yields negative, with particularly big shifts in German, French and Japanese yield curves during June. Worries over the global growth outlook, further fueled by Brexit, have continued to support demand for higher-quality sovereign paper in June. Widespread adoption of unconventional monetary policies, including large-scale bond-buying programs and negative deposit rates, have driven the large increases in negative-yielding debt seen this year. ... The biggest drivers of the total increase during June were seen in longer-dated bonds. For example, German 10-year bund yields swung into negative territory and sub-zero yields moved further out on the curve for Japan -- now out to 17 years. Also, in Switzerland, virtually all sovereign debt carried a negative yield on June 27."