and so forth and so on..
in order to sell stocks short, the seller must arrange for a broker-dealer to confirm that it is able to make delivery of the shorted securities. This is referred to as a "locate.” Brokers have a variety of means to borrow stocks in order to facilitate locates and make good delivery of the shorted security.
The vast majority of stocks borrowed by U.S. brokers come from loans made by the leading custody banks and fund management companies (see list below). Institutions often lend out their shares in order to earn a little extra money on their investments. These institutional loans are usually arranged by the custodian who holds the securities for the institution. In an institutional stock loan, the borrower puts up cash collateral, typically 102% of the value of the stock. The cash collateral is then invested by the lender, who often rebates part of the interest to the borrower. The interest that is kept by the lender is the compensation to the lender for the stock loan.
Brokerage firms can also borrow stocks from the accounts of their own customers. Typical margin account agreements give brokerage firms the right to borrow customer shares without notifying the customer. In general, brokerage accounts are only allowed to lend shares from accounts for which customers have "debit balances", meaning they have borrowed from the account. SEC Rule 15c3-3 imposes such severe restrictions on the lending of shares from cash accounts or excess margin (fully paid for) shares from margin accounts that most brokerage firms do not bother except in rare circumstances. (These restrictions include that the broker must have the express permission of the customer and provide collateral or a letter of credit.)
Most brokers will allow retail customers to borrow shares to short a stock only if one of their own customers has purchased the stock on margin. Brokers will go through the "locate" process outside their own firm to obtain borrowed shares from other brokers only for their large institutional customers.
Stock exchanges such as the NYSE or the NASDAQ typically report the "short interest" of a stock, which gives the number of shares that have been legally sold short as a percent of the total float. Alternatively, these can also be expressed as the short interest ratio, which is the number of shares legally sold short as a multiple of the average daily volume. These can be useful tools to spot trends in stock price movements but in order to be reliable, investors must also ascertain the number of shares brought into existence by naked shorters. Speculators are cautioned to remember that for every share that has been shorted (owned by a new owner), a 'shadow owner' exists (i.e. the original owner) who also is part of the universe of owners of that stock, i.e. Despite not having any voting rights, he has not relinquished his interest and some rights in that stock.
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