Rights issues and rump placings

Before xmas, Kier Group held a rights issue which was something of a flop, with only about a third of the shares being taken up. The left the underwriters and sub-underwriters on the hook, and there was a subsequent "rump placing" that saw them dump a lot of stock below the issue price.

I've never really looked at this, so thought I'd trawl regulatory disclosures to see how Kier Group compared to others. Below are the disclosed percentages of stock that ended up at rump placings from 2015 to 2018. These figures are taken from regulatory filings that relate to rump placings and run from most recent on the far left, through to start of 2015 on the far right (including the dates made it very messy).

In most cases the amounts involved (the shares not taken up) are pretty trivial. During that period, only five got into double figures and only two saw more than 50%. In fact, Kier Group is only beaten by Petropavlovsk in terms of lack of take-up, and then only just, which is hardly great company if you've followed the story of that company. (The other noticeable spike is Lonmin, with 29% not taken up).

Interested to hear from anyone who knows this stuff better than I do if there is anything that I'm missing.