US private equity firm KKR has taken a 5.21% stake in listed German broadcaster ProSiebenSat.1 Media, returning to a company it previously held for eight years.

The buyout group said it decided to reinvest in the company as it is convinced that ProSiebenSat.1 is currently undervalued. KKR joins Mediaset, which owns nearly 25%, and Czech Media Invest, which holds a 10% stake, as the biggest shareholders in the business.