Investing.com - The NFIB's small business optimism index is released on Tuesday. The producer price index for March is also due out.Facebook (NASDAQ:FB) CEO Mark Zuckerberg appears before Congress on Tuesday and Wednesday in response to the company's data scandal. On Wednesday, look for the consumer price index for March and the minutes of the Fed's March FOMC meeting. The oil markets will be awaiting the release of the OPEC monthly report for March on Thursday.BlackRock releases earnings on Thursday. Citigroup (NYSE:C), Wells Fargo (NYSE:WFC) and JPMorgan Chase (NYSE:JPM) all report on Friday. On Friday, the University of Michigan releases the preliminary reading of its consumer sentiment index in April.