Ending Balance = Initial Investment * (1 + Interest Rate)^Number of Years
Plugging in the given values:
Ending Balance = £21,000 * (1 + 0.088)^9
Calculating this:
Ending Balance ≈ £40,782.36
Therefore, the ending balance after 9 years with an annual compound interest rate of 8.8% on an initial investment of £21,000 is approximately £40,782.36.