Question: Are we ever told exactly why Jerry needs the money? His $750,000 deal with the parking lot falls through and he owes GMAC $320,000. He is going to give the kidnappers $40,000, but then it's increased to $80,000. But he sets the ransom at only $1 million. So what is the deal?
Answer: The business deal didn't actually fall through. Jerry needed $750,000 to proceed with it. He tried borrowing the capital from his father-in-law, who refused to lend it to him. Instead, the father-in-law wanted to invest in the deal himself and to give Jerry a small finder's commission. Outraged, Jerry devised the phony kidnap scheme so he could get the money to invest in the parking lot. (He never intended for his wife to be harmed.) Presumably he planned to pay off the kidnappers and partially repay GMAC with some of the $1,000,000 ransom money, and use the rest for the investment deal.