Accounting giant KPMG LLP has been blessing the books of General Electric Co. for 110 years, but the audit currently under way holds significant risks for both companies.

KPMG is under fire for a string of audit failures and scandals, highlighted again Friday in a set of scathing reports by the nation’s top accounting regulator, which is demanding KPMG increase its skepticism and improve the quality of work, particularly at big, complicated clients like GE.

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