The Department of Finance may require taxpayers to use and to furnish tax identification numbers. In the case of individuals, this shall be the Federal Social Security Number, and, in the case of businesses, this shall be the Federal Employer Identification Number.
Del. Code tit. 30, § 306
Taxpayer identification number
30 Del
Official source: Delaware Code Online. Reproduced from public-domain Delaware statutes; confirm against the official source for the current text. Not legal advice.