Dow Jones & Co. beat analysts’ estimates with its third-quarter earnings, as sales jumped 20 percent to $493.3 million, driven in part by growth in online advertising.

The report yesterday was likely to be its last as an independent company ahead of News Corp.’s $5.2 billion purchase of Dow Jones, which is expected to be completed next month. News Corp. also owns The Post.

Dow Jones also predicted that profit for the year will rise 40 percent, excluding certain items, again beating Wall Street estimates.

CEO Richard Zannino said expenses related to the News Corp. takeover lowered earnings by 11 cents a share, causing third-quarter net to fall 87 percent to $13.8 million, or 16 cents a share, from $105.4 million, or $1.26 a share. The year-ago figure was boosted sharply by a one-time gain.

Excluding those special expenses, Dow Jones’ quarterly earnings jumped to $23.1 million, or 27 cents per share, from $9.4 million, or 11 cents per share, a year earlier.