BENGALURU, June 23 (Reuters) - Byju's troubles have mounted as its auditor Deloitte and three board members cut ties with the Indian education technology startup that was once an investor darling valued at $22 billion.

The firm attracted billions of dollars from investors across the globe and went on an acquisition spree during the COVID-19 pandemic that boosted demand for online education services.

BYJU'S ACQUISITIONS

* Aakash Educational Services - Byju's bought IPO-bound Aakash, which offers coaching for various competitive exams across India, for $950 million in 2021.

* Great Learning - Byju's acquired Great Learning, which counts Indian cricketer Virat Kohli as an ambassador, in 2021 for $600 million. It offers online learning material for professional and higher education courses.

* WhiteHat Jr - WhiteHat Jr specialises in offering classes on online coding to students aged 6-18, and Byju's bought it for $300 million in 2020.

* Toppr - It offers exam-preparation material for school children in India. Byju's bought it for $150 million in 2021.

* Osmo - U.S.-based Osmo offers learning educational games for children aged 3-8, and was acquired by the Indian company for $120 million in 2019.

* Epic - The California-based reading platform Epic was acquired by Byju's for $500 million in 2021 as part of its plans to expand its U.S. footprint. Epic has more than 40,000 audio books and videos.

BYJU'S' GLOBAL INVESTORS

* Blackrock - invested in 2020, but has twice slashed the value of its investment in recent months.

* Naspers, now known as Prosus, has parked $536 million in Byju's since 2018 and holds a 10% stake.

* Peak XV, formerly Sequoia Capital India, is among early backers.

* General Atlantic first invested in Byju's in late 2018, with $200 million its last investment in 2020

* UBS invested about $150 million during the pandemic, in 2021.

* Qatar's sovereign wealth fund participated in the Indian startup's funding round of $250 million last year.

* Chan-Zuckerberg Initiative of Meta founder Mark Zuckerberg and philanthropist Priscilla Chan participated in a 2016 investment round.

Sources: Byju's website, venture capital and private equity database PitchBook, annual reports of investors. (Reporting by Nandan Mandayam in Bengaluru; editing by Robert Birsel)