The case of Wisconsin Central Ltd. v. United States, 2017 revolved around the issue of whether stock options should be taxed as money under the Railroad Retirement Tax Act (RRTA). The RRTA imposes a tax on "compensation", which it defines as "any form of money remuneration". Wisconsin Central Ltd., along with other railroads, argued that stock options did not fall under this definition and therefore should not be subject to taxation. However, the U.S government disagreed and claimed they were taxable compensation. The Supreme Court ruled in favor of Wisconsin Central Ltd., stating that when Congress adopted the RRTA in 1937, “money” was understood as currency issued by a recognized authority as a medium of exchange. Therefore, employee stock options are not considered 'money' for purposes of taxation under this act because they are not mediums of exchange but rather speculative assets tied to company performance.

In the dissenting opinion for Wisconsin Central Ltd. v. United States, Justice Breyer argued that stock options should be considered taxable compensation under the Railroad Retirement Tax Act (RRTA). He pointed out that Congress intended to tax all forms of remuneration and there was no reason why stock options should be treated differently from other types of benefits like free rail passes or hotel discounts which are taxed under RRTA. Furthermore, he contended that treating money as the only form of remuneration would create a loophole allowing companies to avoid taxes by paying employees in kind rather than cash. The majority's interpretation, according to him, contradicts common sense understanding and undermines the purpose of RRTA - providing pensions for railroad workers.