Surcharge & Cess: Applicable based on income thresholds.

Alternative Tax Regimes:

$115BA$: 25% for new manufacturing companies (post-01-03-2016). Restrictions on deductions.
$115BAA$: 22% for domestic companies. Restrictions on deductions.
$115BAB$: 15% for new manufacturing companies (post-01-10-2019). Strict conditions, restrictions on deductions.
MAT ($115JB$): 15% (or 9% for IFSC units) of Book Profit if normal tax < MAT.

Carry Forward & Set-off of Losses ($79$):

Closely held companies (non-start-up): 51% voting power continuity required.
Eligible start-up companies: Conditions relaxed for 10 years.
Unabsorbed depreciation is exempt from $79$ conditions.
No set-off against undisclosed income ($79A$).

Trusts

Religious or Charitable Trust:
- Exemption ($11, 12$): Income from property/voluntary contributions exempt if applied for charitable/religious purposes.
- Conditions: Property under trust, charitable/religious purpose, registration ($12A, 12AB$), audit, 85% application of income.
- 15% of income can be accumulated freely.
- Anonymous donations ($115BBC$): Taxed @30% if exceeds threshold (5% of total donations or ₹1 lakh).
- Forfeiture of Exemption ($13$): If applied for private religious purpose, particular community, non-specified investments, or benefit of interested person.
- Exit Tax ($115TD$): Accreted income taxed at MMR if trust converts, merges inappropriately, or fails to transfer assets on dissolution.
Securitisation Trust ($115TCA$): Income exempt in trust's hands, taxable in investor's hands as if direct investment. TDS ($194LBC$).
Business Trust (REIT/InvIT) ($115UA$):
- Specific income (interest/dividend from SPV, rental income for REIT) exempt in trust's hands, taxable in unit holder's hands.
- Other income taxable in trust's hands at MMR.
- TDS ($194LBA$).
Investment Fund ($115UB$): Non-business income exempt, business income taxable in fund's hands (company/firm @ tax rate, others @ MMR). Certain losses passed through to unit holders. TDS ($194LBB$).

Mutual Association: Principle of mutuality applies (no one can trade with himself). Income from mutual activity generally not taxable. Exceptions for insurance business, trade/professional associations.

2. Tax Management, Return & Assessment

Return of Income ($139$):
- Mandatory Filing: For companies/firms, or individuals/HUFs exceeding basic exemption limit. Also for NRs with foreign assets/signing authority.
- High-Value Transactions: Mandatory filing for individuals/HUFs (even if below basic exemption) if specified conditions met (e.g., cash deposit > ₹1 Cr, foreign travel > ₹2 lakh, electricity > ₹1 lakh).
- Forms: ITR-1 (Sahaj), ITR-2, ITR-3, ITR-4 (Sugam), ITR-5, ITR-6, ITR-7.
- Due Dates: Nov 30 (TP report), Oct 31 (audited accounts/company), July 31 (others).
- Late Filing Fee ($234F$): ₹1,000 (income $\le ₹5$ lakh), ₹5,000 (income $> ₹5$ lakh).
- Loss Return ($139(3)$): Must be filed by due date to carry forward most losses (except unabsorbed depreciation, HP loss).
- Belated Return ($139(4)$