What happened?
An activist investor has found its way inside Outerwall (OUTR), the company best known for its network of Redbox DVD kiosks around the country. In a filing with the Securities and Exchange Commission, young California-based hedge fund Engaged Capital said it and its affiliates now have a roughly 14% stake in the company.

In the filing, Engaged Capital said it bought the shares because they "were undervalued and represented an attractive investment opportunity." According to a report in Bloomberg, the hedge fund is pushing Outerwall to consider strategic alternatives, including a sale of the company.

This is not the first time a hedge fund has carved out a stake in Outerwall and pushed for changes. In 2013, Jana Partners became a shareholder, exiting its investment the following year after Outerwall initiated share buybacks.

Does it matter?
Engaged Capital isn't (yet) in the top tier of activist investors. Yet in its brief life (it was founded in 2012) it's been effective; it entered medical device concern HeartWare (NASDAQ: HTWR) and helped push for that company to rescind a pricey takeover of cardiology implant maker Valtech Cardio. Late last month, HeartWare did so.

And that was with barely more than a 1% stake in the company, so we can assume Engaged Capital has a strong chance of getting its way with Outerwall.

That company's investors are likely very receptive to a push for change. Its stock price has dropped by nearly 60% over the past year, and by 26% so far in 2016. A onetime investor favorite thanks to the success of Redbox, technology has moved on and Outerwall is well past its stock market darling phase.

Engaged Capital's involvement makes it a stock to keep an eye on again. We can bet that the hedge fund's presence will result in a major shift in direction of some kind, just like it did in the case of HeartWare.