Amazon has formed a fund to back startups that could incorporate its Alexa voice technology, and has revealed its first seven investments.

The Qualcomm and SoftBank-backed wearable fitness tracker maker's stock has almost doubled since it went public on Thursday.

The high-end mattress startup raised the series B funding in a Norwest Venture Partners-backed round at a $555m valuation.

The Comcast-backed men's grooming product retailer has now raised almost $150m, after raising series D money that will fund hiring and marketing.

Evonik has participated in a funding round for Wiivv, a provider of custom-made, 3D printed insoles.

Corporate-backed Partech Ventures led a series B round for the wireless service provider.

The fitness tracker producer initially hoped to raise $448m through its initial public offering, but has increased the pricing to $20 a share.

The media company has invested an undisclosed amount to increase its stake in the online property listings site by 5%.