Home Equity Line of Credit (HELOC) — Firstmark Credit Union is a home equity line of credit from Firstmark Credit Union. The ongoing APR is Rates as low as 6.875%APR; Variable APR ranges from 6.875% to 9.875% depending on credit profile and loan to value.; Maximum APR is 18%.. Loan terms: 10-year draw period with interest-only payment options.