Anthony Sicari and Esther Sicari v. Commissioner of Internal Revenue

JON O. NEWMAN, Circuit Judge:

This appeal concerns the duty of the Commissioner of Internal Revenue (the “Commissioner”) to use reasonable diligence, when sending a notice of deficiency to a taxpayer, in ascertaining the taxpayer’s “last known address.” A notice sent to such address is a prerequisite to collection of an income tax deficiency, and the mailing of a proper notice starts a 90-day time period in which the taxpayer may challenge the assessment of the deficiency in the Tax Court. Usually, disputes as to whether the required notice was properly addressed concern a taxpayer who has…