What information must my bank give me before I sign a home equity line of credit?

Because your HELOC is an 'open end consumer credit plan' (a type of revolving credit line) that is 'secured by the consumer’s principal dwelling' (meaning your home is used as collateral to guarantee the loan) [cite:us-title15-consumer-credit-sec1637a], the law requires very specific written information. Regarding your confusion about interest rates, the bank must provide a 'description of the manner in which such rate will be computed' and a 'description of the manner in which any changes in the annual percentage rate will be made' [cite:us-title15-consumer-credit-sec1637a]. This must include the specific 'index or margin to which such changes in the rate are related' and a 'source of information about any such index' [cite:us-title15-consumer-credit-sec1637a]. To address your concern about how much the rate could jump, they must state the 'maximum amount by which the annual percentage rate may change in any 1-year period or a statement that no such limit exists' [cite:us-title15-consumer-credit-sec1637a]. To prevent surprises regarding costs, the bank must provide an 'itemization of any fees imposed by the creditor in connection with the availability or use of credit under such plan, including annual fees, application fees, transaction fees, and closing costs' [cite:us-title15-consumer-credit-sec1637a]. They must also provide an 'estimate, based on the creditor’s experience... of the aggregate amount of additional fees that may be imposed by third parties (such as governmental authorities, appraisers, and attorneys)' [cite:us-title15-consumer-credit-sec1637a]. Most importantly, regarding your home, the bank must provide a 'statement that... any extension of credit under the plan is secured by the consumer’s dwelling; and... in the event of any default, the consumer risks the loss of the dwelling' [cite:us-title15-consumer-credit-sec1637a]. This warning must be presented clearly and must 'precede all of the other required disclosures' [cite:us-title15-consumer-credit-sec1637a]. It is uncertain if your specific credit union has already provided these via the email you received, as the law requires these disclosures to be provided 'at the time the creditor distributes an application' [cite:us-title15-consumer-credit-sec1637a].