What happened

Shares of Digital Turbine (NASDAQ:APPS) gained 35.4% in September, according to data from S&P Global Market Intelligence. The company, which specializes in the distribution and monetization of mobile apps, didn't have much news to share last month, but some large investors did increase their holdings of its stock.

So what

Digital Turbine's trading volume skyrocketed on Sept. 15 and Sept. 16 -- two otherwise perfectly normal days in this company's corner of Wall Street. It's true that mobile device titan Apple (NASDAQ:AAPL) held a closely watched event on Sept. 15, but that presentation skipped over the next generation of iPhones to focus on new iPads and wearables. Digital Turbine's investors are more interested in the smartphone market.

The stock's trading volumes told the real tale here. Both ordinary shares and call options changed hands at approximately double their normal volumes, pointing to large purchases by institutional investors. SEC filings will eventually show us exactly who executed these market-moving transactions.

A rendering of a smartphone with several colorful arrows rising from the screen.

Image source: Getty Images.

Now what

The no-news jump was part of a massive surge for the stock in 2020 as a whole. Digital Turbine's share price is up by 400% year to date, and has set fresh all-time highs that are more than 900% above the low point it hit this spring. The company recently signed long-term app discovery deals with the three largest U.S. wireless networks, and smartphone sales are starting to recover from their dismal lows. The company's revenues nearly doubled year over year in its fiscal first-quarter 2021, which ended June 30 and was reported on in August. Digital Turbine is finding a high-growth groove after 22 years of business operations.