Unexplained investments treated as income trigger higher tax, barred deductions, surcharge and possible additional penalty. Unexplained investments not recorded in books may be deemed income if the assessee offers no satisfactory explanation; such included income is taxed under a special regime at a higher rate with no deductions or set offs allowed, attracts a surcharge on that tax, and may attract an additional penalty imposed by revenue officers unless the income was disclosed in the return and tax under the special regime paid within the relevant year.