Employment Law Questions? Ask an Employment Lawyer.
The law on this issue varies by jurisdiction. In most states, the issue has never been determined with certainty by an appellate court.
However, as an example, in California, the Unemployment Insurance Appeals Board has determined that a 20% reduction in pay is sufficient to qualify an employee for unemployment benefits, under the theory that the originally agreed upon employment conditions differ substantially from the new employment conditions.
I hope I've answered your question. Please let me know if you require further clarification. And, please provide a positive feedback rating for my answer -- otherwise, I receive nothing for my efforts in your behalf.
Thanks again for using Justanswer!