FBR Capital analyst William Bird views comments from the Internal Revenue Service on Friday at the ABA meeting as incrementally positive for Yahoo (YHOO). Robert Wellen, IRS Associate Chief Counsel, said Friday that his agency's recent notice "is not a description of future guidance" and that "nothing in this notice affects an immediate retroactive date." The analyst believes the comments take one Yahoo risk off the table, namely the retroactive treatment of potential new rules. However, anything shy of a definitive tax ruling on Yahoo's planned spinoff of its Alibaba (BABA) holdings falls short of fully resolving tax uncertainties, Bird tells investors in a research note. No timeline was given for how long the IRS plans to study the spinoff questions under tax code Section 355, analyst points out. He keeps an Outperform rating on Yahoo. The stock is up 23c to $30.97 in pre-market trading. Alibaba, which has 63% percent of its outstanding shares come off lockup today, is up 77c to $65.19 in trading before the opening bell.