The global bond rout continues to play out today with long-end yields surging higher once again. 30-year yields in the US are now clipping the 5% mark and that's a very important threshold to be wary about. It's not the first time this year but in previous tries, yields did not manage to firmly hold a break above 5%. This time around though, the pressure valve might be of a different build.Outside of the US, we're also seeing long-end yields continuing to rise. 30-year yields in the UK are up another 4 bps to 5.73% while 30-year yields in France are up about 2 bps to 4.52% currently. Even earlier today, we saw 30-year yields in Japan hit an unprecedented 3.28%.But amid everything that is going on, the key threshold above for US bonds might be one of the most important. That especially with a keen focus on US labour market data this week as well as the Fed outlook.Here's a primer as to what this development is signaling for markets: The US yield curve continues to steepen post-Jackson Hole This article was written by Justin Low at investinglive.com.