Robert Kovacev commented on the impact of the Internal Revenue Service's (IRS) use of regulations and sub-regulatory guidance during an American Bar Association (ABA) Section of Taxation meeting on May 13, covered by Tax Notes. He noted the agency's practice of identifying listed and other reportable transactions via notices that subject taxpayers to penalties and possible criminal sanctions for failure to comply with reporting requirements. According to Kovacev, the litigation regarding the IRS's reportable transaction regime highlights the tension between the advantages to the agency of using sub-regulatory guidance — it can be issued relatively quickly and answer questions applicable to large taxpayer populations — and the disadvantages to taxpayers, who must comply with guidance that hasn't gone through notice and comment.