Playground Ventures the VC fund co-founded by Android inventor and former Google exec Andy Rubin that sits alongside an eponymous incubator/startup studio and is making some big bets in areas like artificial intelligence and new generations of hardware is raising more money. A Form D filed with the SEC notes that Playground Ventures is in the process of adding another $15 million into its coffers. The filing notes that none of the sum has yet to be raised.

Relatively speaking, $15 million a modest figure: since 2015, it looks like the Playground group, which includes the Playground Global incubator and Playground Ventures, has disclosed about $242 million in funding as part of a projected$300 millionfundraise, and what appears to be a bigger plan to raise $500 million. We have contacted the company to ask if it can elaborate more on whether this $15 million is one more segment in that wider effort, or if it is for another, different purpose.

Specifically, this latest funding is for Playground Ventures Affiliates II. Two previous Playground Ventures filings at the SEC include Playground Ventures, which is from 2015 and covers the$242 million raise; and Playground Ventures II, which dates from November 2016 and is the filing to raise $500 million. Well update this as we learn more.

Notably, en route to raising $300 million to date, Playground has picked up a number of strategic backers like Google, HP and Foxconn, which together with others put in $48 million towards the running total.

Why? Everyone likes to back a winning team, and by virtue of Rubins experience with Android and Google, and the impressive backgrounds of others on the team (including the creator of QuickTime, the co-creator of Danger, the creator of the first big video codec and many others), Playground has one of the best track records around. And getting involved at the LP level gives these companies a chance to work early on with startups that have the potential to become big.

Up to now, Playground has served as a vehicle for backing some big ideas.

The full portfolio today includes deep linking startup Branch, French high-end audio maker Devialet, driverless tech startup Nauto, the new phone company Essential and more. But notall of them may be flying. Just earlier this week we reported that AR company CastAR appears to have shut down.

In some cases, the companies have been incubated and have Playgrounds support and network access in exchange for equity, but no investment. In other cases, Playground has invested.

Read more: