The definition of "small business" for the purposes of section 704B of the ECOA (as added by section 1071 of DFA) is included in subjection 704B(h). It is the "same meaning as the term 'small business concern' in section 3 of the Small Business Act (15 USC 632)." At 15 USC 632 you'll find the rather long definition of "small business concern" in subsection (a) - Criteria. It's subject to further definition by the Administrator (of the SBA). The SBA has established size criteria for small business concerns at 13 CFR 121.201.
I presume that the Bureau will point to 15 USC 632(a) and 13 CFR 121.201 for its definition of "small business" when it issues final rules amending Regulation B to implement section 704B of ECOA. In general, the size standards say it's a business with annual receipts of under $750,000.
Although the language of the DFA makes section 1071 effective on the transfer date, it can't be enforced until after implementing rules are issued.
John S. Burnett
Professional Compliance Nerd since 1976
Bankers' Threads User #8