also: Macroeconomics; microeconomics; Keynesian economics, monetarism, and supply-side economics. Economies of scale Achievement of lower average cost per unit through increased production. Economies of scale The decrease in the marginal cost of production as a firm's extent of operations expands. Economies of scope Scope economies exist whenever the same investment can support multiple profitable activities less expensively in combination than separately. Economies of vertical integration Produced by achieving lower operating costs by owning all components of production and sometimes sales outlets rather than contracting with companies in the outside marketplace. EDGAR (Electronic Data Gathering and Retrieval) The Securities & Exchange Commission uses Electronic Data Gathering and Retrieval to transmit company documents such as 10-Ks, 10-Qs, quarterly reports, and other SEC filings, to investors. Edge Act corporation Corporationchartered by the Federal Reserve to engage in international banking. The Board of Governors acts on applications to establish Edge Act corporations and also examines the corporations and their subsidiaries. Named after Senator Walter Edge of New Jersey, who sponsored the original legislation to permit formation of such organizations. See also: agreement corporation. Edge corporations Specialized banking institutions, authorized and chartered by the Federal Reserve Board of Governors in the U.S., that are allowed to engage in transactions of a foreign or international character. They are not subject to restrictions on interstate banking. Foreign banks operating in the U.S. are permitted to organize and own an edge corporation. Education IRA A type of individual retirement account enabling the contribution of up to $500 per year tax free for each child up to the age of 18 by the parents in the family. Effective annual interest rate An annual measure of the time value of money that fully reflects the effects of compounding. Effective annual yield Annualizedinterest rate on a security computed using compound interest techniques. Effective call price The strike price in a marketredemption provision plus the accrued interest to the redemption date. Effective convexity The convexity of a bond calculated using cash flows that change with yields. Effective date In an interest rate swap, the date the swap begins accruing interest. Effective debt The total debt owed by a firm to its creditors. Effective duration The duration calculated using the approximate duration formula for a bond with an embedded option, reflecting the expected change in the cash flow caused by the option. Measures the responsiveness of a bond's price - taking into account that expected cash flows will change as interest rates change due to the embedded option. Effective Interest Rate The annual rate at which an investment grows in value when interest is credited more often than once a year. Effective margin (EM) Used with SAT performance measures, the amount equal to the net earned spread, or margin of income, on assets in excess of financing costs for a given interest rate and prepayment rate scenario. Effective net worth Net worth plus subordinated debt. Effective rate A measure of the time value of money that fully reflects the effects of compounding. Effective sale A sale based on the most recent round-lot price, which determines