What is a top-up loan, and how is it different from a buyout?

A top-up, or further advance, means borrowing more from your current lender against your property's increased value, without moving banks. It avoids a full buyout's DLD discharge and re-registration costs, but you stay on your existing bank's rates. A buyout, by contrast, moves the whole loan to a new lender to secure a genuinely better deal.