Savers with the Halifax, Woolwich, Bristol & West and Northern Rock all need to have a total of at least pounds 100 in qualifying accounts by 31 December to share in the handouts.
So if you are running down your savings to help pay for Christmas you should beware of going lower than pounds 100 in case you forget, or do not have time, to top them up again for the end-of-the-year deadline.
Watch out, too, for any minimum balance requirement on accounts from which you are making withdrawals. If you go below you risk the closure of the account and forfeiting your bonus. A hundred pounds is the end- of-year balance needed to qualify for the basic bonuses - a handout of pounds 250 from Bristol & West; probably pounds 500 or more from others.
Some very small savers stand to miss out on these basic windfalls even if they have not been spending. When Northern Rock and Bristol & West made their windfall announcements earlier this year they said savers at that time with, respectively, pounds 50 and less than pounds 100, could qualify if they topped up their accounts to the same pounds 100 threshold by the end of this year. With the Halifax and Woolwich you had to have pounds 100 when the windfall was announced, so if you have not touched your savings since you should be okay.
Other savers could lose even more than the basic handouts if they do not take care. The Halifax, Woolwich and Bristol & West have all said they will pay extra bonuses to bigger savers or (in the case of B&W) those who have been with the society for longer. For some of these savers their total handout could be in the thousands.
With the Halifax and Woolwich these additional handouts are on offer to those who had pounds 1,000 or more of savings on, respectively, 25 November, 1994 and 31 December, 1995. But the size of the top-up will also depend your balance on yet-to-be announced dates in the spring. Both societies say they will tell savers the exact dates shortly, and the Halifax says its will be in February. So if you are spending now remember that you may need to do some fast rebuilding in the New Year to maximise the extra payout.
Many of the savers who opened accounts with Bristol & West in 1994 or before are also eligible for a top-up based on their lower balance on two dates yet to be revealed. The society will not say whether these savers, who had to have a balance of at least pounds 100 when the windfall was announced in April, will reduce their entitlement by taking money out now. As well as this top-up their basic payout will be pounds 500, compared with pounds 250 for other savers with the society.
By comparison, Alliance & Leicester savers are pretty much in the clear now. Earlier this month they voted overwhelmingly for a windfall deal that should see them get free shares worth pounds 1,000 or more each in April.To qualify, savers with A&L should only need to keep their accounts open with the relevant minimum balance, as low as pounds 1 in some cases, until April. That said, if the society should be bid for before it reaches the stock market, an outside predator might offer more to those savers with bigger balances.
The Halifax also says savers who only qualify for the basic handout can reduce balances to as little as pounds 1 from 1 January and still qualify for their free shares, due in June. Woolwich and Bristol & West advise savers to keep pounds 100 with them until conversion, in the autumn and summer, respectively.
Where you have savings with a society that has not yet announced a windfall deal it is also a good idea to keep your total balance in accounts that give membership of the society (called share accounts) above pounds 100. This should give the best chance of qualifying for any windfall. Birmingham Midshires and Skipton building societies are two hot favourites to be taken over next.
q All the societies have helplines. These are: Halifax 0800 88 88 44; Woolwich 0345 022 033; Bristol & West 0800 88 66 33; Northern Rock 0345 44 88 66; Alliance & Leicester 0990 785163.