Possible Clues:

• A commitment must be made here
• When did you start selling stocks, Mr. Marquand?
• Where advance is inevitable on Fot Niop?
• When you stop making a profit, but can't turn back
• Rubicon is ace!
• Crucial juncture to clue 'on purpose'?
• Where one becomes finally committed
• Can't go back after this
• You can't go back from it
• Line beyond which investments yield nothing?