Sometimes, the investment companies get extensions. With one company, I have a single, national muni bond fund. While I have already received the year-end annual account statement and the percentage of dividend income exempt from my state income taxes, I am still waiting for the 1099B form because I wrote one check on the account last year. I need to see the 1099B form because it will tell me how to report the sale on Form 8949. I do not expect any of the shares I sold to have their cost basis reportable to the IRS (because I bought them before 1/1/2012, using FIFO), but until I see the 1099B form I won't know for sure (I had a surprise last year from my other investment company due to a tiny wash sale which frigged up the cost basis by a few dollars).
I probably could complete my state income tax forms but I owe them some money so there is no hurry. Still, it's kinda annoying to have to wait an extra 2 weeks to get this form because I am due a hefty refund on the federal side and would like to get the process started.