A company is required to file its proxy statements with the SEC no later than the date proxy materials are first sent or given to shareholders. You can see this filing by using the SEC's database, known as EDGAR. Enter the company’s name here and select the appropriate company to view its SEC filings.
To view the most recent proxy statement, select the most recent filing that has the title "DEF 14A." It's called a "DEF 14A" because it's the "definitive," or final, proxy statement. "14A" refers to the fact that proxy statements are filed pursuant to Section 14(a) of the Securities Exchange Act of 1934.