Savers who want the security of a fixed-rate return need to watch out for "breakage" costs - the penalties financial institutions will charge if funds are withdrawn from the account before the full five-year period has expired.

These charges are similar to the redemption penalty lenders can impose on the early redemption of fixed-rate mortgages.

Table 2 sets out the fixed-rate products on offer from the financial institutions ranked by the interest rate paid. Irish Nationwide offers the best fixed rates, but accounts must be opened before June 30th.

But all providers, except for An Post, will impose penalties for early withdrawals.

Though An Post will not impose a breakage penalty, the interest rate it is prepared to pay savers - 4 per cent - is well below the best on offer. Bank of Ireland will allow a limited penalty-free annual withdrawal, though again its interest rate is relatively low.

Because of these breakage penalties, savers who are not sure they can have their funds tied up for the full five years should avoid fixed-rate SSIAs, apart from An Post, and to a lesser extent Bank of Ireland.

Savers also need to remember that under SSIA rules all early withdrawals are taxed at 23 per cent.

So early withdrawals from fixed-rate SSIAs, apart from An Post, could be hit by both a "breakage" charge and a tax penalty of 23 per cent.

Savers who expect market interest rates to fall over the next two years may be tempted to go for a fixed-rate account.

But these accounts, apart from the An Post product, are only suitable for savers who have a high degree of confidence that they will not need their funds within the five-year period, because of the penalties for early withdrawals.

"Breakage" penalties are levied by financial institutions in the event of early full withdrawal or transfer to another SSIA with another product provider.

While the calculation of the specific break cost may vary from one financial institution to another, the following is an example of a typical formula: Amount withdrawn multiplied by the unexpired saving term multiplied by the differential between prevailing market rates for the remaining term and the fixed rate.

However, "breakage" costs could be negated if fixed rates increase above the original rate obtained during the term.