Fundamentally speaking, rising earnings estimates and the consequent rating upgrade for Volkswagen AG Unsponsored ADR imply an improvement in the company's underlying business. Investors should show their appreciation for this improving business trend by pushing the stock higher. Harnessing the Power of Earnings Estimate Revisions Empirical research shows a strong correlation between trends in earnings estimate revisions and near-term stock movements, so it could be truly rewarding if such revisions are tracked for making an investment decision. Here is where the tried-and-tested Zacks Rank stock-rating system plays an important role, as it effectively harnesses the power of earnings estimate revisions.