Given the following marginal cost estimates associated with obtaining additional interest$-$checking account funding:$$

Market interest rate $1\mathrm{.}0\%$

Servicing costs: $2\mathrm{.}3\%$ of balances

Acquisition costs: $0\mathrm{.}2\%$ of balances

Deposit insurance costs $=0\mathrm{.}25\%$ of balances

Required reserves $=10\%$ required reserves

Float $=3\%$

What is the estimated$$marginal cost of obtaining additional interest$-$checking balances?