Eligibility for SUGAM ITR-4: resident individuals, HUFs and resident firms with presumptive business income may use the simplified return.
Eligibility to file Form SUGAM (ITR-4) is limited to resident individuals, resident HUFs (other than not ordinarily resident), and resident firms (excluding LLPs) deriving business or professional income computed under presumptive provisions of sections 44AD, 44ADA or 44AE. Explicit exclusions bar persons with foreign assets/signing authority/income, directorships, unlisted equity holdings in the previous year, income above the prescribed limit, more than one taxable house property, brought forward or carry forward losses, assessments where tax was deducted in another's hands, claims under double taxation provisions or deduction under section 91, certain agricultural income, and incomes taxable under specified special heads.

ITR form eligibility limited to resident individuals with salary, single house and non lottery other income; foreign interests excluded.
Form SAHAJ (ITR 1) is available only to resident individuals whose taxable income arises solely from salaries or family pension, income from a single house property without brought forward or current losses under that head, and other sources excluding lottery winnings and race horse income, provided they do not fall into disqualifying categories such as foreign assets, foreign income or signing authority, income requiring apportionment, directorships, unlisted equity shareholdings, tax assessed on income with TDS in another person's hands, claims for double taxation relief, specified deductive claims, agricultural income above a small threshold, or total income above the prescribed upper limit.