Thorsten Heins, chief executive officer of BlackBerry, speaks during the launch of the BlackBerry Z10 smartphone in Sydney, Australia, on Monday, March 18, 2013. BlackBerry, the Canadian smartphone maker that rolled out a new lineup in January, said on March 13 one of its "established partners" is buying 1 million BlackBerry 10s, the biggest order in the company's history. Photographer: Brendon Thorne/Bloomberg
Thorsten Heins, chief executive officer of BlackBerry, speaks during the launch of the BlackBerry Z10 smartphone in Sydney, Australia, on Monday, March 18, 2013. BlackBerry, the Canadian smartphone maker that rolled out a new lineup in January, said on March 13 one of its "established partners" is buying 1 million BlackBerry 10s, the biggest order in the company's history. Photographer: Brendon Thorne/Bloomberg

BlackBerry Ltd., the maker of smartphones that aren't quite as smart as its competitors' smartphones, may have a savior after all. The company this afternoon said it has a tentative $4.7 billion buyout offer from a group led by a fellow Canadian company, Fairfax Financial Holdings Ltd.

The price would be $9 a share, about 3 percent more than BlackBerry's closing price last week. Fairfax is BlackBerry's largest shareholder. This post isn't about the deal itself, however, so much as it is about the conflicting interests that can arise when companies turn to Big Four accounting firms for consulting advice.

On Sept. 20, the same day that BlackBerry said that it would eliminate a third of its staff and record a $960 million inventory writedown, Bloomberg News reported that BlackBerry had hired PricewaterhouseCoopers LLP to evaluate the company for potential buyers. The article said the information came from two people with knowledge of the move and that "a team of accountants and lawyers" from the accounting firm "have been working at BlackBerry since August."

A Pricewaterhouse spokeswoman in Toronto, Kiran Chauhan, declined to comment at the time. She didn't immediately return my phone calls today, either.

So, take a wild guess which Big Four accounting firm happens to be the outside auditor for Fairfax. The answer is Pricewaterhouse, of course. So that team of accountants and lawyers shouldn't be working at BlackBerry much longer. There are those pesky rules about auditor independence, after all. For instance, if you're an accounting firm, you really shouldn't be giving deal advice to a company that is trying to get bought by one of your audit clients. BlackBerry's auditor is Ernst & Young LLP.

Consider this something for other public companies to keep in mind the next time they go looking for a deal adviser.

(Jonathan Weil is a Bloomberg View columnist. Follow him on Twitter.)