They are duty bound to hold stakes in Footsie stocks. But when dealings start, Halifax shares will be owned by former members of the society with tracker funds probably not accounting for a solitary share between them. So early dealings are likely to be chaotic, with fund managers scrambling to build suitable positions as the price probably runs away from them.
Although many Halifax members will no doubt quickly cash in their chips, the possibility of stock market turmoil, and no doubt representations from certain fund managers, has prompted the Footsie Indices Committee to ponder whether the so-called "fast track" entry should be withdrawn from Halifax and its shares excluded from Footsie until the quarterly review following the listing.
But the committee will not give harassed fund managers much of a breather even if "fast track" status is withdrawn.
Halifax is due to float in early June. The next committee meeting will take place in late June with index newcomers slotted in around the end of the month. So tracker funds will, even if the building society is denied immediate inclusion, only have a few weeks of Halifax trading before the biggest building society of them all goes into Footsie and they are obliged to be on board.
The market continued to recover from Friday's jitters with Footsie ending 21.4 points higher at 3,993.8 as, during London trading, New York once again defied the merchants of gloom and their predictions of imminent crash or correction. The reappearance of corporate activity helped sentiment. The huge US aero merger and rather more modest excursions in the domestic insurance broking and engineering businesses offered renewed hope that bid action could transform the market atmosphere.
The corporate window could be much more difficult to open after next year's election and companies with aggression in mind could be tempted to flex their muscles, particularly if shares slip lower.
Commercial Union, the insurance giant, was back in the limelight, gaining 15p to 680p, a peak. Allianze, the German group, remains the favoured predator but BAT Industries is said to have made unreciprocated advances. It has been suspected for some time that BAT could demerge into stand- alone financial services and tobacco groups. A deal with CU, or another group, would strengthen its Eagle Star and Allied Dunbar financial operations. BAT fell 12p to 478.5p.
The insurance broking deal involved Lloyd Thompson bidding for JIB. Lloyd rose 1.5p to 174p and JIB 21p to 130p. Sedgwick and Willis Corroon made headway. The other deal could involve FKI, an engineer, and Newman Tonks, a building materials group. After Newman disclosed FKI had made an approach its shares jumped 26.5p to 129p; FKI dipped 1.5p to 200p.
British Aerospace shrugged off the proposed $45bn Boeing/McDonnell Douglas merger, rising 11p to 1,136.5p. Societe Generale Strauss Turnbull and Credit Lyonnais Laing were among houses offering buy advice.
T&N gained 5p to 175.5p on suggestions GKN had made a pounds 250m offer for its high-tech materials division.
Rexam, the paper and packaging group, eased 1p to 337p after Merrill Lynch trimmed its profit forecasts. It is now looking for pounds 170m this year against pounds 177m and pounds 195m (pounds 205m) for next. Carlton Communications improved 14p to 508.5p as UBS said buy.
Asda, the superstores group, moved ahead 2.25p to 124p, highest for five years. Figures are due on Thursday.
Oxford Biomedica was steady after Friday's disastrous debut, closing up 3p to 51.5p against the 88p placing. Highams, a business services group, enjoyed a strong opening, hitting 91p and closing at 87.5p from its 72p placing. Cirqual, a metals group, switched to full listing after less than six months on AIM. The shares were unchanged at 177.5p.
Memory Corporation, which repairs defective computer chips, slipped 2.5p to 42.5p after raising pounds 1.36m through a placing at 45p. AND International, the electronic publisher, built on Friday's exuberance, gaining a further 25p to 210p.
Eyecare Products slumped 9.5p to 18p after a profit warning and flat profits from Gibbs Mew, the brewer, pushed shares 89p lower to 210p.