Slack Technologies Inc, a corporate messaging and collaboration software startup, has received inquiries about a potential takeover from technology companies including Amazon.com Inc, Bloomberg reported on Thursday.

A deal could value the company at least $9 billion, Bloomberg reported citing people with knowledge of the matter.

Slack is a platform where employees can send messages, collaborate, organize and share files. The technology also integrates with a wide variety of business software - such as Salesforce.com Inc and Microsoft Corp's Skype - so employees can do all their work within Slack.

San Francisco-based Slack has raised more than $500 million from venture capitalists and was valued at $3.8 billion at its last private financing round a year ago.

Both, Amazon and Slack were not immediately available to comment outside of regular US business hours.