How accurate are the budget figures on imdb?

The only source we have is a Wikipedia entry for the 1989 film Parenthood, which states that the film grossed $126 million against a $20 million budget. This data comes from Wikipedia and does not reference IMDb. Because the evidence does not mention IMDb or its budget listings, we cannot evaluate how accurate IMDb’s figures are for any film. To determine IMDb’s accuracy, one would need sources that compare IMDb’s reported budgets to other reliable data such as studio reports, industry publications, or official financial statements.