Between the time of making a bid and financial close, many of the financial parameters on which the bid is based may change. The most significant risk is that interest rates may change during that period.
The risk of interest rate variation prior to financial close should rest with the private party from such a time as they are reasonably able to mitigate the risk through a hedging instrument.
Additional mitigation options may include documenting commitments regarding the specific pricing regime in the project development agreement. This allows commitments that may benefit the project overall to be entered into before financial close, and provides for a sharing of the risks associated with these commitments.
The allocation of financial parameter risk depends on the circumstance of each project, but is ultimately driven by value for money considerations, i.e. which party is best positioned to take the risk at least cost.