“When I entered the valuation field, I quickly became very dissatisfied with the available means of estimating DLOM,” writes Marc Vianello (Vianello Forensic Consulting LLC). His dissatisfaction extended to the restricted stock studies, pre-IPO studies, transactional databases, and option-based models. “After all, there were no empirical studies,” he says. He conducted his own study, and you can read about it in his free e-book, Empirical Research Regarding Discounts for Lack of Marketability. The book has intros by Francis A. Longstaff, Ph.D. (UCLA), who conducted a study in 1995 that relies on stock options to estimate the DLOM, and Michael Gregory (Michael Gregory Consulting), former IRS engineering territory manager and champion of the IRS DLOM Job Aid.