Tribune Company’s debt was downgraded by Standard & Poor’s on Monday, just as the media group’s shareholders were preparing to vote on Tuesday on a proposed $8.2bn sale to real estate mogul Sam Zell.

Standard & Poor’s lowered Tribune’s rating one notch from BB- to B+, predicting that the company’s performance would further deteriorate in the year ahead. S&P’s said it expected to make a further downgrade after the buy-out was completed.