TD Ameritrade 2018 Annual Report

29 Institutions pay us an aggregate marketing fee based on the weighted average yield earned on the client IDA assets, less the actual interest paid to clients, a servicing fee to the TD Depository Institutions and the cost of FDIC insurance premiums. Fee revenues earned under this agreement are included in bank deposit account fees on our consolidated financial statements. Interest-earning assets — Consist of client margin balances, segregated cash , deposits paid on securities borrowing and other cash and interest-earning investment balances. Interest rate-sensitive assets — Consist of spread-based assets and client cash invested in money market mutual funds. Investment product fees — Revenues earned on fee-based investment balances . Investment product fees consists of fees earned on client assets invested in money market mutual funds, other mutual funds and through investment programs such asAdvisorDirect, ® Essential Portfolios, Selective Portfolios and Personalized Portfolios. Investment product fees also includes fees earned on client assets managed by independent registered investment advisors utilizing our trading and investing platforms. IRA accounts (Individual Retirement Arrangements) —A personal trust account for the exclusive benefit of a U.S. individual (or his or her beneficiaries) that provides tax advantages in accumulating funds to save for retirement or other qualified purposes. These accounts are subject to numerous restrictions on additions to and withdrawals from the account, as well as prohibitions against certain investments or transactions conducted within the account. We offer traditional, Roth, Savings Incentive Match Plan for Employees (SIMPLE) and Simplified Employee Pension (SEP) IRA accounts. Liquid assets — Liquid assets is a non-GAAP financial measure. We consider liquid assets to be an important measure of our liquidity, including our ability to meet corporate cash flow needs, fund potential operational contingencies and support our business strategies. We define liquid assets as the sum of (a) corporate cash and cash equivalents, (b) corporate investments, less securities sold under agreements to repurchase, and (c) our regulated subsidiaries' net capital in excess of minimum operational targets established by management. Corporate cash and cash equivalents includes cash and cash equivalents from our investment advisory subsidiaries. Liquid assets represents available capital, including any capital from our regulated subsidiaries in excess of established management operational targets. We include the excess capital of our regulated subsidiaries in the calculation of liquid assets, rather than simply including regulated subsidiaries' cash and cash equivalents, because capital requirements may limit the amount of cash available for dividend from the regulated subsidiaries to the parent company. Excess capital, as defined under clause (c) above, is generally available for dividend from the regulated subsidiaries to the parent company. Liquid assets is based on more conservative measures of net capital than regulatory requirements because we generally manage to higher levels of net capital at our regulated subsidiaries than the regulatory thresholds require. Liquid assets should be considered as a supplemental measure of liquidity, rather than as a substitute for GAAP cash and cash equivalents. Liquidation value — The net value of a client's account holdings as of the close of a regular trading session. Liquidation value includes client cash and the value of long security positions, less margin balances and the cost to buy back short security positions. It also includes the value of open futures, foreign exchange and options positions. Margin accounts — Brokerage accounts in which clients may borrow from us to buy securities or for any other purpose, subject to regulatory and Company-imposed limitations. Market fee-based investment balances — Client assets invested in mutual funds (except money market funds) and investment programs such as AdvisorDirect, ® Essential Portfolios, Selective Portfolios and Personalized Portfolios on which we earn fee revenues that are largely based on a percentage of the market value of the investment. Market fee-based investment balances are a component of fee-based investment balances . Fee revenues earned on these balances are included in investment product fees on our consolidated financial statements. Net interest margin (" NIM ") — Ameasure of the net yield on our average spread-based assets . Net interest margin is calculated for a given period by dividing the annualized sum of bank deposit account fees and net interest revenue by average spread-based assets . Net interest revenue — Net interest revenue is interest revenues less brokerage interest expense. Interest revenues are generated by charges to clients on margin balances maintained in margin accounts, the investment of cash from operations and segregated cash and interest earned on securities borrowing/securities lending . Brokerage interest