(Updates to add enterprise value, updates shares)

March 8 (Reuters) - Pluralsight Inc said Vista Equity Partners had increased its all-cash offer to buy the U.S. learning software company after investor groups said the initial bid was not sufficient and complained about how Pluralsight had run its sale process.

Shares of Pluralsight rose 7.4% to $22.08 on Monday after the private equity firm raised its bid to $22.50 per share from $20.26 per share

The enterprise value for the amended deal is about $3.8 billion, a Pluralsight spokesperson said. On Dec. 13, Vista Equity first agreed to acquire Pluralsight in a deal valuing the learning software company at $3.5 billion.

Monday's revised offer represents an 18.5% premium to Pluralsight's close on Dec. 11.

Vista will commence the tender offer on or before March 10, with the deal expected to close in the second quarter of this year, Pluralsight said.

Vista, led by billionaire Robert Smith, has over $73 billion in assets under management, and specializes in investing in enterprise software, data and technology companies.

Silicon Slopes, Utah-based Pluralsight sells software to companies through its Skills and Flow product lines, which helps offer courses and analytics services.

(Reporting by Akanksha Rana in Bengaluru, additional reporting by Joshua Franklin in New York; Editing by Devika Syamnath and Amy Caren Daniel)