There are highly contentious arguments among critics over using a higher or lower discount rate for the PPP. A recent analysis of the procurement options for the Pennsylvania Turnpike monetization (Foote et al. 2008) used different discount rates, further supporting this argument by applying lower discount rates to the public monetization scenario. The lower discount rate for the public monetization scenario was equivalent to the Pennsylvania Turnpike Commission's (PTC) borrowing cost of 4.5%, whereas the discount rate of a private lease was estimated at 7.75%. The PTC discount rate was based on the yield of PTC's AA/Aa3 debt in today's market, and assumed that the state would pursue to public monetization as proposed in Act 44, which includes raising tolls on the Turnpike and adding tolls on I-80 (contingent to federal approval). The higher discount rate for the private monetization scenario was estimated based on the weighted average cost of capital, assuming 6.65% for private borrowing costs (for Baa rated corporate bonds), a cost of equity of 12.5%, and assuming an equity/debt ratio of 19% to 81% (based on the Indiana Toll Road concession equity/debt ratios). A critique to the Foote et al. analysis (Poole and Samuel 2008) suggested that the PTC discount rate should have been raised to account for risk, owing to the uncertainty of adding tolls on I-80. Grout (2003) recounts a decades-long controversy over this issue, and concludes that there are powerful arguments for using a higher discount rate for the PPP delivery mechanism.