Bill Ackman's first stock was Wells Fargo – and Warren Buffett was a big reason why he bet on the bank

• Bill Ackman's first stock was Wells Fargo, and Warren Buffett was a key factor in his choice.
• The billionaire invested in the bank as a business-school student with only $40,000 to his name.
• Ackman determined Wells Fargo, which counted Buffett as a big shareholder, was oversold at the time.

Bill Ackman made bank with the first stock he ever bought — and Warren Buffett was a key reason why he placed the wager.