What if I take my $1,000 and I borrow an additional $1,000 at a 5% interest rate? Now I can buy $2,000 of VTI. Then, when the market goes up 20%, I have $2,400. Once I repay the loan with interest ($1,050), I am left with $1,350. The market went up 20% but I increased my investment by 35%. That’s the power of leverage.