He presumably would have done so by relying on a special IRS "safe harbor" rule relating to the taxation of a service partner's receipt of such interests, but that rule emphatically does not apply to an interest when sold to a retirement plan, which is supposed to be measured by its true fair market value.
Hologic, like many employers, had moved to a safeharbor ESPP with reduced benefits after accounting rule changes in 2006 required companies to recognize a compensation expense for ESPPs.
Yet EU officials have expressed concern as to the jurisdiction of the FTC to enforce the safeharbor, as well as dissatisfaction with the fact that numerous regulatory agencies adjudicate disputes under the safeharbor, which may result in inconsistent rulings and uncertain application of the rule.