Under the International Financial Reporting Standards (IFRS) that SoftBank uses, companies have wide latitude to determine how much they think portfolio companies are worth—and therefore how much profit they report to investors. It's unclear whether any company has tried to determine paper profits for tech startups on the scale SoftBank is now using. "I don't believe we've ever seen an attempt to record this magnitude of income with respect to unquoted equity investments," said Robert Willens, a tax expert in New York.