The declared rate of return compounded semi annually equivalent to the effective rate of return 10.25% per annum is:

The effective rate of return is 10.25% per annum, and the nominal rate is compounded semi-annually (twice per year).

The relationship between effective rate and nominal rate for semi-annual compounding is:

$(1 + \text{Effective Rate}) = (1 + \frac{\text{Nominal Rate}}{2})^2$

Since the effective rate is 10.25%, we have:

$(1 + 0.1025) = (1 + \frac{r}{2})^2$

where $r$ is the nominal rate.

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$1.1025 = (1 + \frac{r}{2})^2$

Taking the square root of both sides:

$\sqrt{1.1025} = 1 + \frac{r}{2}$

$1.05 = 1 + \frac{r}{2}$

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$1.05 - 1 = \frac{r}{2}$

$0.05 = \frac{r}{2}$

$r = 0.05 \times 2$

$r = 0.10$

Converting to percentage: $r = 10\%$ per annum

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Therefore, the declared rate of return compounded semi-annually is 10% p.a.