State tax filing

While it is true that New York has a very aggressive telecommuting law, the facts and circumstances of this particular case, I believe would be more appropriately governed by case law. In Matter of Thomas Huckaby, 5 NY 3d 427 the Court of Appeals concluded that a taxpayers work at home in Tennessee was for his own convenience. The taxpayer, over a period of two-years, only worked in NYS for 25% of the time. The court found that those activities rose to the level of "minimal connection" required by due process to justify taxation in New York State. I cite specifically to this:

"In Zelinsky, we found the minimal connection called for by due process on account of the taxpayer's "physical presence in New York and because he . . . purposefully avail[ed him]self of the benefits of an economic market in" New York (Zelinsky, 1 NY3d at 97 [internal quotation marks omitted]). Here, petitioner objects that, read and applied literally, the convenience of the employer test would allow New York to tax 100% of the income of a nonresident who worked out of his employer's place of business in New York just one day a year. He argues that due process demands proportionality in order to prevent this presumed overreaching. Whether due process would countenance this particular result taxation of 100% of the income of a nonresident who spends a trivial amount of time working in New York is simply not before us. We conclude that the minimal connection required by due process plainly exists in this case where petitioner accepted employment from a New York employer and worked in his employer's New York office approximately 25% of the time annually. Moreover, the amount of time that petitioner spent working in New York 25%is significant enough to satisfy any rough proportionality requirement called for by due process."

Here, I would argue that the single day worked in NYS, would not rise to the level of "minimal connection" required under due process. Thus, I would advise that you should only allocate income to New York State on the prorata basis of one New York workday, over your total amount of workdays in all other locations. 

My background to advise you on such matters is that I'm a licensed enrolled agent, former New York State auditor, and currently work in a State and Local Tax group, specializing in New York State tax matters, at a large law firm.