Microsoft is adding a new layer of security for spreadsheets and Office documents with the purchase of US company Prodiance.

Prodiance makes software that monitors changes made to corporate documents to prevent fraud.

"The acquisition of Prodiance enables deeper integration of compliance-related solutions into future versions of Office and SharePoint," said Albert Chew, senior product manager for Office.

Prodiance had already been working with Microsoft as a partner will now become a wholly-owned subsidiary.