The 23-Year-Old Programmer Behind Robintrack

Robintrack has become an indispensable data source on day traders.

If the Robinhood trader has become symbolic of the young retail investors thronging to the stock market during this volatile period, it is because financial media and Wall Street had a window into the activity on the platform, which has over 13 million users. Everyone, from analysts at Goldman Sachs and Barclays, to Bloomberg, CNBC and Investopedia, have to thank a 23-year-old with a deep interest in building, maintaining and sharing data-based tools on his own computer.

In March 2018, Casey Primozic, an undergraduate student at Valparaiso University built Robintrack as a side project while he worked part-time at a cryptocurrency startup. As the name suggests, the website tracks the number of Robinhood users holding different stocks over time. This information can be used to chart the relationship between price and popularity of a particular stock and build lists that rank the largest changes in popularity in a day, a week, or even a month. It’s a simple idea, but no one else thought to do it. Not even the hedge funds who the creator says visit Robintrack now to download its data.

"The data was sort of just hidden on the Robinhood site..."

"I had built other tracking websites for video games and music, and I saw an opportunity to do the same thing for Robinhood traders. The data was sort of just hidden on the Robinhood site, it was kind of nestled in there. I didn’t see anyone doing anything with it, but it seemed like it could have some value," said Primozic, a Seattle resident, whose name you’ll find at the bottom of the Robintrack page in its signature neon pink font. He has been a user on the trading platform for years.

  • Retail trading activity has soared during the pandemic
  • Robinhood added 3 million users in the first 4 months of 2020
  • Robintrack was built as a side project by a college student in March 2018
  • It is used as a data source by financial institutions, media, the general public
  • The website now sees 165,000 individual users visit a week

"Robinhood publishes that popularity number publicly. You don’t have to have a Robinhood account to access it or anything like that. They have provided a service to the community, which I really admire. I just collect that data from their API hourly for all the different stocks available on their platform," he explained.

There’s nothing stopping financial institutions sending their tech teams after the data from Robinhood today, but Primozic has been collecting it for years and has the historical data that paints the complete picture they are after. "As far as I know, I'm the only person who's been collecting this data for any meaningful amount of time," he said.

Hertz stock price and popularity since 2018. Source: Robintrack.

Programming and Building

Growing up as the son of a former IBM executive and an editor, Primozic was always around computers at an early age and developed a love for programming. He was also inspired by the cryptocurrency community. "There's a lot of innovation going on," he said. "A lot of people building stuff who are regular people who work in tech rather than people who are parts of big institutional firms and whatnot."

Robintrack is one of many projects he has shared online, but none have seen anything close to its success. In the week before I spoke with him, the website saw 165,000 different users visit and close to 300,000 sessions. It experienced a surge in traffic starting in April as interest in retail investors grew and more people began citing Robintrack. The Twitter page, which automatically shares changes in stock popularity on Robinhood in the day, now has over 31,000 followers.

"It’s definitely kind of a stars aligned situation where the data I’m providing is both of high interest to the public and as well as all the retail traders entering the market," said Primozic commenting on the success. It’s all still new and exciting enough that he tells his mother the number of people that visited the site that day when they talk on the phone.

Stocks with the biggest popularity increases in the last month. Source: Robintrack.

"The most recent increase in visitors has definitely been motivating me to write a few improvements and features for the site," said Alex Jensen, Primozic's childhood friend who helped build certain aspects of the website. "He had made a few similar sites previously - mostly for online games. Robintrack stood out from those as being for a more general audience. I remember wanting him to push it live as fast as possible."

Wall Street Comes Knocking

One of the things financial historians will note about this time is the fascination with small investors. The media and Wall Street are used to following "smart money," but very rarely do they pay this much attention to, and comment on, the decisions of retail investors as a group.

When Robintrack, a website run by a young individual holding a full-time job elsewhere, looked like a great way to gain insight, it had to go through some vetting. "There’s been several different banks and hedge funds who have reached out to me to get more information from a regulatory aspect, trying to figure out how I’m sourcing the data, trying to figure out if it’s something they can actually use or if it’s a valid source for them," said Primozic, who feels a big sense of responsibility now to keep his data accurate and convey no bias.

He also doesn’t plan on ever charging for access to the website because he wants to keep the data accessible. He runs advertising on it to pay for things like server costs, but believes subscriptions would go against what Robinhood is trying to do. He said, "I wanted to match the fact that they’re providing the data free for anyone to use to try and make the markets more transparent. Hedge funds and other big institutions, they’ll have access to things like this in other ways."

Robintrack creator Casey Primozic
23-year-old Casey Primozic, Robintrack's creator.

Robinhood, of course, knows about the website. An employee spotted it its early days and shared it on the company Slack. It was impressive enough that a recruiter at the company reached out and called Primozic in for an interview. As the site gains more followers, many have gotten in touch, including those in high places.

"The biggest impact it’s had for me personally is the amount of people I’ve got to meet and get in contact with. People who run ETF-issuing funds and people working at prominent financial institutions and people trading. All these high-profile Twitter accounts retweet my content, stuff like that," he said.

The fact that what he built was a big deal really dawned on him when the Robintrack Twitter account posted on a day the stock markets were closed. It indicated all values as zero since there were no changes. "Previously no one really cared, I only had a couple hundred people following. Now that I have tens of thousands of followers it was seen as a comedic event, a corporate flub in a way. It was the most popular tweet of the entire month!"

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