Given a list of integers, write a function to find the largest product that can be obtained by multiplying three integers from the list. The list will always contain at least three integers.

Example:

Input: [-5, -5, 1, 3]
Output: 75

The function should return 75 because (-5) x (-5) x 1 x 3 = 75.

Constraints:

• The list will always contain at least 3 integers.
• The integers can include both positive and negative numbers