Parentheses and Periods

Which sentence is correct?

Version #1
A small number of users takes home the lion’s share of the profits (spoiler: it’s not all due to insider trading).

Version #2
A small number of users takes home the lion’s share of the profits. (Spoiler: it’s not all due to insider trading.)

My instincts tell me that version #2 is better, because the period breaks up the two points and thus is cleaner. I asked my colleague Paul Stregevsky, who agreed:

“Version 2 is the only version that is correct. When the parentheses hold an entire clause, the parentheses must be preceded by a period, and the parenthetical clause must have its own period, within the parentheses.”