I just began graduate school in September of 2017 and have been receiving fellowship stipend payments since then. However, I missed the January 16, 2018 filing date for estimated quarterly taxes on the fellowship income. I am currently waiting on my 1099-DIV forms from Schwab, which won't be available until February but I don't want to incur a penalty for not filing by the January 31, 2018 deadline for quarterly taxes. Can I file by the January 31, 2018 deadline for the fellowship income and then amend my return with the information from my 1099-DIV once I receive it?
You can, but you might also be able to find your 1099-DIV information on the Schwab website now.
I don't believe that Schwab will release the 1099-DIV information until February 1 at the earliest, at least for the online download. I'm not quite sure how to estimate my taxable dividends from my account statements at this time. Is there an additional fee to amend the return if I take that route?
no, there is no additional fee. Downloads from brokerage firms take a longer time because they have to set up a special file with all the codes in it for the download. The 1099-DIV form itself may show on their web site long before it is mailed or available for download. If not, though, you can indeed amend your return after you get it.
When you amend, though, you may still receive an Underpayment penalty for not sending in enough estimated tax for the year. Your statement shows the full amount of dividends you received for the year, and you should use that to enter on a 1099-DIV even though you haven't received one yet.
The worst that will happen is you won't know the amount that are called qualified dividends, but you can just leave that field blank. It's for the portion of your dividends that could be taxed at a lower capital gains rate. All that means is you would still do an amend later to add in that field, and you may get back a small refund from the amendment.