MITIGATION OF EFFECT OF LIMITATION, Adjustment to be made, § 3801. MONEY OR MONEY'S WORTH Transfers in gross estate, § 812 (b) (5). MONTH Definition, § 930 (c). MUNICIPALITIES Contributions to Estate taxes, §§ 812 (d), 861 (a) (3). Army and Naval Forces, § 22 (b) (14). MUTUAL DITCH COMPANIES Exempt from income tax, § 101 (10). INSURANCE COMPANIES OTHER THAN LIFE OR MARINE Amortization of premium and accrual of discount, § 207 (d). Credits against net income, § 207 (g). Deductions from gross income, § 207 (b) (4). Capital losses, § 207 (b) (4) (F). Depreciation, § 207 (b) (4) (D). Foreign corporations, § 207 (e). Investment expenses, § 207 (b) (4) (B). Foreign mutual insurance companies, § 207 (a) (5). No United States insurance business, § 207 (a) (6). Net operating losses, § 208. Net premiums defined, § 207 (b) (2). MUTUAL INVESTMENT COMPANIES See "Regulated Investment Companies." MUTUAL MARINE INSURANCE COMPANIES MUTUAL SAVINGS BANKS Exempt from income tax, § 101 (2). MUTUAL TELEPHONE COMPANIES Exempt from income tax, § 101 (10). N NATURAL GAS COMPANY Definition, § 735 (a) (1). Not in operation during base period, § 735 (b) (5). Definition, § 735 (a) (5). NATURAL GAS UNIT NAVY CONTRACTS Laws applicable, § 651. NAVY FORCES Abatement of income tax of, § 421. Additional allowance, § 22 (b) (13). Additional estate tax, § 939. Definition, § 3797 (a) (15). Mustering out pay, § 22 (b) (14). NET CAPITAL GAIN Definition, § 117 (a) (10). NET CAPITAL LOSS Definition, § 117 (a) (11). NET ESTATE Definition, §§ 812, 930 (b). NET GIFTS Definition, § 1003 (a). Exclusion from gifts, § 1003 (b). NET INCOME Corporations, § 21. Credits against. See "Credits Against Net Income."' Definition, § 21 (a). Estates, § 162. Excess profits tax, § 711. Individuals, § 21. Insurance companies other than life or mutual, § 204 Life insurance companies, § 201 (c) (7). Mutual insurance companies other than life or marine, § 207 (b) (4). Partnerships, § 182. Trusts, § 162. Unjust enrichment tax, § 700. NET LONG-TERM CAPITAL GAIN Definition, § 117 (a) (8). NET LONG-TERM CAPITAL LOSS Definition, § 117 (a) (9). NET OPERATING LOSS Amount of carry-back and carry-over, § 122 (b). Corporation credits against net income, § 26 (c). NET OPERATING LOSS-Cont. Deduction, § 122. Definition, §§ 26 (c) (2), 122 (a). Estates and trusts, § 170. Limitations with respect to carry-backs, § 322 (b) (6). Overstatement of carry-backs, § 294 (e). Personal holding companies, § 505 (c). Unused excess-profits tax credit carry-backs, §§ 276 (d), 292 (c). NET PREMIUMS Mutual insurance companies other than life or marine, NET SHORT-TERM CAPITAL GAIN Definition, § 117 (a) (6). NET SHORT-TERM CAPITAL LOSS Definition, § 117 (a) (7). NEW CAPITAL See Equity Invested Capital." NON-BUSINESS DEBTS Deductibility from gross income, § 23 (k) (4). NON-BUSINESS EXPENSES Deductibility from gross income, § 23 (a) (2). NON-DEDUCTIBLE ITEMS Amounts paid to holders of life or terminable interest, § 24 (d). Betterments, § 24 (a) (2). Indebtedness to purchase endowment contract, § 24 Indebtedness to purchase single-premium life insur- Items in excess of $50,000 for five consecutive years, Inter-corporation losses, § 24 (b) (1). Inter-fiduciary-beneficiary losses, § 24 (b) (1). Life insurance premiums, § 24 (a) (4). New buildings, § 24 (a) (2). Permanent improvements, § 24 (a) (2). NON-EXEMPT PROPERTY Definition, § 373 (e). NON-INTEREST-BEARING OBLIGATIONS Issued at discount, § 42 (b). NON-PROFITABLE ORGANIZATIONS NOTICE Demand for payment of tax, § 3655. NOTICE OF DEFICIENCY Estate taxes, § 871 (a) (1). Jeopardy assessment, § 273 (b). NOTICE OF FIDUCIARY RELATIONSHIP Failure to exercise, § 117 (g). Individual to be taxed, §§ 400-404. Stock, personal holding company, § 503 (a) (3). OPTIONAL STANDARD DEDUCTION Allowance, § 23 (aa) (1). Husband and wife, § 23 (aa) (4). In lieu of certain deductions and credits, § 23 (aa) Method and effect of election, § 23 (aa) (3). Short period, § 23 (aa) (5). OPTIONAL VALUATION Gross estate, § 811 (j). Definition, § 3797 (a) (2). PARTNERSHIP RULE Amortization deduction, § 190. Computation of partnership income, § 183. Segregation of items, § 183 (b). Capital gains and losses, § 183 (b) (1). Ordinary net income or loss, § 183 (b) (2). Credits for foreign taxes, §§ 131 (a) (4), 186. §§ 131 (a) (4), 186. Definition, § 3797 (a) (2). Different taxable years from partners, § 188. Net operating losses, § 189. Partners taxable, § 182. Partnership returns, § 187. Property acquired by, gain or loss, § 113 (a) (13). Stock ownership in personal holding company, § 503 PARTY TO A REORGANIZATION Definition, § 112 (g) (2). Time of payment, § 822 (a) (1). To clerk of United States Court for China, § 920 (a). Authority of clerk to act as collector, § 921. To collector, § 920 (b). PAYMENT OF ESTIMATED TAXES Assessment, § 59 (b). Computed by collector, § 56 (i). In general, § 59 (a). Penalty for failure, § 294 (d). PAYMENT OF EXCESS PROFITS TAXES Consolidated return, § 730 (c). Deferment in case of abnormality, § 710 (a) (5). PAYMENT OF GIFT TAXES Extension of time, § 1008 (b). Time of, § 1008 (a). Voluntary advance payment, § 1008 (c). PAYMENT OF INCOME TAXES Collected at source on wages, §§ 1623-1625. Consolidated returns, § 141 (c). Deficiencies determined by Board, § 272 (b). Installments, § 272 (i). Jeopardy assessments, § 273 (i). Estates and trusts, §161 (b). Estimated taxes, § 59. PENSION PLAN See "Employees' Trusts.'' PENSION TRUSTS See "Employees' Trusts."' Capital gain or loss, § 117 (b). Ball and sagger clay, § 114 (b) (4). PERCENTAGE DEPLETION-Cont. Flake graphite, § 114 (b) (4). Fluorspar, § 114 (b) (4). Gilsonite, § 114 (b) (4). Gross income from property, § 114 (b) (4). Metal mines, § 114 (b) (4). Mica, § 114 (b) (4). Oil and gas wells, § 114 (b) (4). Vermiculite, § 114 (b) (4). PERJURY Penalties, § 3809. PERIOD HELD Determination of, capital gains and losses, § 117 (h). PERIOD FOR WHICH DEDUCTIONS AND CRED- ITS TAKEN General, § 43. PERIOD IN WHICH ITEMS OF GROSS INCOME See "Accounting Periods."' General rule, § 42 (a). Non-bearing interest obligations issued at discount, § 42 (b). Short-term obligations issued on discount basis, § 42 (c). PERMANENT IMPROVEMENTS Non-deductibility, § 24 (a) (2). PERSON Definition, §§ 145 (d), 3797 (a) (1). PERSONAL EXEMPTION See "Credits Against Net Income."' PERSONAL EXPENSES Non-deductibility, § 24 (a) (1). PERSONAL HOLDING COMPANIES Additional credit or refund for prior taxable years, § 506 (j). Election as to deficiency dividends, § 506 (j) (1). Administrative provisions, § 508. Corporations making consolidated returns, § 501 (c). Definition, § 506 (c) (1). Deficiency dividends credit or refund, § 506. Deficiency paid, § 506 (a). Unpaid deficiency, § 506 (b). Claim required, § 506 (d). Denied in case of Fraud, § 506 (f). No return filed, § 506 (f). PERSONAL HOLDING COMPANIES-Cont. Definition, § 501. Exceptions, § 501 (b). General rule, § 501 (a). Gross income requirement, § 501 (a) (1). Gross income of insurance companies other than life Dividends-paid credit. Effect of deficiency dividends paid, § 506 (c) (2). For taxable year in which paid, § 506 (c) (2) (A). Exemption from excess profits tax, § 727. Extension of time for payment of income tax by, § 56 Foreign Personal Holding Companies. See "Foreign Liquidation of, § 56 (c) (2). Personal holding company income defined, § 502. Annuities, § 502 (a). Dividends, § 502 (a). Gains from transactions in Commodities, § 502 (c). Stock and securities, § 502 (b). Income from estates and trusts, § 502 (d). Income to shareholder, use of corporate property, § 502 (f). Interest, § 502 (a). Mineral, oil or gas royalties, § 502 (h). Personal service contracts, § 502 (e). Rents, § 502 (g). Rate for taxable years after 1941, § 506 (h). Stock ownership, § 503. Constructive ownership, § 503 (a). Application of family-partnership and option Constructive ownership as actual ownership, § 503 Family ownership, § 503 (a) (2). Option rule in lieu of family-partnership rule, |