As an AI language model, I can provide some examples of economic policy changes that have impacted global stock markets in recent times. It is important to note that stock markets are influenced by a myriad of factors, including economic policies. Here are ten potential economic policy changes impacting global stock markets this year:

1. Trade policies: Changes in tariffs, trade agreements, or trade tensions between major economies can significantly impact stock markets worldwide.

2. Monetary policy decisions: Central bank actions such as interest rate adjustments, changes in quantitative easing measures, or modifications to monetary policy frameworks can create ripples in global stock markets.

3. Fiscal stimulus measures: Implementation of fiscal stimulus packages, tax cuts, or infrastructure spending from various governments can impact stock market sentiments globally.

4. Government regulations: Policy changes and regulations in sectors like technology, finance, or energy can result in both positive and negative impacts on stock markets.

5. COVID-19 response policies: Measures taken to combat or mitigate the economic impact of the pandemic, such as lockdowns, stimulus packages, and vaccination campaigns, can influence stock market performance.

6. Energy policies: Changes in policies related to fossil fuels, renewable energy, or carbon emissions can have significant effects on stock markets, especially in the energy sector.

7. Housing policies: Regulatory changes or initiatives related to housing markets, such as interest rates, mortgage regulations, or housing affordability policies, can impact related sectors and influence stock markets.

8. Exchange rate policies: Adjustments in exchange rates or monetary policies aimed at managing currency values can affect the competitiveness of international companies and influence stock market performance.

9. Financial regulations: Changes in financial regulations, such as stricter rules for banks, enhanced consumer protection laws, or modified governance standards, may impact investor confidence and subsequently affect stock markets.

10. Political stability measures: Political events, elections, government transitions, or geopolitical tensions can introduce uncertainty, potentially impacting stock markets as investor sentiment responds to changes in stability.

Please note that the specific impact and ranking of these policy changes in global stock markets may vary depending on various factors and the timing of events.