Groupon (GRPN) shareholder Nick Nemeth urged the company's board to modernize its consumer platform, revamp its brand strategy, and accelerate share repurchases, saying the stock remains significantly undervalued, the company said Wednesday.

Nick Nemeth called for a redesign of Groupon's iOS, Android and web platforms, along with greater emphasis on influencer-led and user-generated marketing targeting younger consumers.

He also urged Groupon to speed up share repurchases using free cash flow, excess cash reserves and potential proceeds from its stake in SumUp, which has reportedly been viewed as a possible IPO candidate, the company added.