Could carpetbagging be back? Five years after a small army of windfall hunters gave up on their campaign to convert Britain's remaining building societies into banks, 2006 could be the year in which the mutual sector once again proves profitable for speculators.
The windfall frenzy of the late Nineties followed a series of demutualisations in which organisations including Halifax, Alliance & Leicester and Northern Rock shed their building society status, awarding free shares worth thousands of pounds to millions of members.
The carpetbagging gravy train was not finally derailed until 2001, when Nationwide - which remains the UK's largest society by some margin - defeated attempts by carpetbaggers who wanted it to demutualise. That spelt the end of similar efforts at around five other societies.
This year, however, more than 100,000 building society members are in line for windfalls. Their societies are being taken over by larger rivals, rather than converting to banking status, but members are still getting the free money.
Two weeks ago, the board of the Lambeth Building Society announced that its 70,000 members would get cash windfalls of at least £400 if they backed a merger with Portman Building Society. It followed an announcement in January from Leeds Building Society. It is taking over the Mercantile, where 30,000 qualifying savers and 4,000 qualifying borrowers are in line for bonuses of at least £100 if the deal goes ahead.
Gordon Robinson, chief executive of the Mercantile, says that while he believes in mutual organisations' advantages over public companies owned by shareholders, many smaller societies are struggling to stay on top of costs.
"Taking into account this maturing marketplace, with its regulatory requirements, demands for ever more sophisticated IT and greater competition, we decided that the long-term interests of our members would be best served by seeking a partner who can bring the benefits of greater size," Robinson says.
Robert Sharpe, Portman's chief executive, says he expects to see further consolidation in the building society sector - already down to 61 societies from more than 150 around 20 years ago - for similar reasons. "If the market remains as competitive as it is now, some of the smaller societies will find it more and more difficult to cope with operating costs," he warns.
In which case, what's to stop a new generation of carpetbaggers targeting the smaller building societies in order to join the party? To become a member of a society, savers can open an account, often with as little as £100, and earn interest on their money while they're waiting for a windfall. It's a no-lose gamble.
Rachel le Brocq, of the Building Societies Association, confirms that qualifying members will almost always be in line for windfalls when two societies merge. "There's no legal requirement for bonuses to be paid in these cases, but it has become standard practice in recent times," she says.
The prospect of a new round of building society windfalls is already attracting interest from potential carpetbaggers. Users of internet sites such as The Money Bag (themoneybag.com) and Moneysavingexpert.com, for example, have begun discussing whether Portman's announcement will trigger similar deals elsewhere.
However, there are two major obstacles any windfall seeker must tackle. First, it isn't possible to campaign for your society to merge with a larger rival, in the way that members previously used to group together to trigger votes on whether a society should demutualise.
Second - and even more seriously - the vast majority of building societies now have measures in place to deter carpetbaggers. Most require new members to assign any future windfall rights to charity, so even if you spot a potential deal, it may be impossible to benefit from it.
Nevertheless, the consolidation of the building society sector means anyone with an account at a smaller player should certainly maintain their membership. And there is a small group of societies - all of which could be potential takeover targets due to their small size - which do have fewer restrictions on new members.
Moreover, carpetbaggers wrestling with their consciences don't have to worry about benefiting from a society turning its back on the mutual sector. This time, the windfalls on offer are from organisations that will remain mutually owned.
Societies in the firing line
The following building societies do not require new members to assign windfall rights to charity, although they may have other restrictions in place.
None has announced specific plans to merge with larger societies, but all nine have assets of £750m or less, making them smaller than Lambeth Building Society.
Open to local residents only: Cambridge, City of Derry, Hinckley & Rugby, Vernon building societies.
Higher opening balances for non-locals: Shepshed, Swansea building societies.
Members of green organisations only: Ecology Building Society.
No restrictions: Catholic, Hinckley & Rugby (selected accounts), Saffron Walden building societies.