Another day, another mid-cap meltdown. This time, it's former market darling and enterprise telco Vocus Group, which announced a profit downgrade well after dusk on Tuesday (7:.0pm to be precise). That's not a good look – and that's just for starters!

Vocus shares were off 26.6 per cent in early trading on Wednesday, from $3.35 to $2.46, just short of RCG Corporation's front-on smash with the yoghurt truck on Monday (27 per cent). Isn't it amazing how something can be a $2.1 billion company at 9.59am but a $1.5 billion company at 10am?