<P> The main focus is on mathematics and science, where the concepts are visually explained and in context using modern digital animations and moving illustrations, all embedded within short videos (15 - 20 minutes long). The app has received criticism for a few issues such as lack of depth in some areas, overly simplistic treatment of some basic topics, and lack of within - lecture student - teacher interaction . In spite of the adverse critical opinion and competition from other players (including Edtech startups and traditional education firms), the app has enjoyed tremendous popularity . BYJU'S reports to have over 15 million users overall and about nine lakh paid subscribers on an annual basis and an annual retention rate of about 90% . </P> <P> BYJU'S operates roughly on a freemium business model where a paid subscription is required for most of the content . </P> <P> As of April 2018, the company has raised around $244 million . The major investors and stakeholders include Chan Zuckerberg Initiative (CZI), Sequoia Capital, Sofina, Lightspeed Venture Partners, Verlinvest, Aarin Capital and Times Internet (Times of India group). This was the first investment from CZI (co-funded by Facebook founder Mark Zuckerberg and Priscilla Chan) in Asia . </P> <P> As per the company filings with the Ministry of Corporate Affairs, BYJU'S became a unicorn and is valued at US $1 billion (INR 6,505 Crore) in March 2018 . </P>

Who is the owner of byju's learning app
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