Hackers Are Emptying ATMs with a Single Drilled Hole and $15 Worth of Gear 9 years ago
From a 2013 reddit AMA: "Each ATM is different. We do 12,500, but have ones with metal cases that reach 26k."
From a 2010 time article: "The average size machine can hold as much as $200,000, though few do. In off hours, most machines contain less than $10,000."
In the article they cite a Philadelphia theft case where a single stolen machine held $96,000.