Sprenkle's formula for the value of a warrant to an investor (equation 2 in appendix C) involved three unknowns: the expected extent of the stock's appreciation in price by the warrant's expiry date; the standard deviation of the stock's anticipated price distribution at expiry; and the "price" the investor was prepared to pay for a warrant's leverage. The price of leverage would be negative for a risk-averse investor, zero for a risk-neutral investor, and positive for a risk-seeking investor.

Donald MacKenzie, An Engine, Not a Camera, loc. 536