Interest on deposits for availing bank guarantee is business income includible in 'book profit' for purposes of section 40(b).

Interest on deposits for securing bank guarantees is business income and includible in book profit under section 40(b). Interest on deposits for availing bank guarantee constitutes business income and must be treated as part of 'book profit' for purposes of computing obligations under section 40(b), and therefore is included in the computation of book profit rather than excluded from commercial receipts affecting disallowances and remuneration calculations.