CU fell 46p to 1,076p; GenAcc 45p to 1,360p.
The insurers, due to merge to create CGU, have been hit by storms in Canada and the US and fierce competition.
Charterhouse Tilney expect CU to produce profits of pounds 55m, down from pounds 102, and GenAcc pounds 75m, compared with pounds 114m.
Analyst Eamonn Flanagan is keen on the shares and declares: "The merger offers significant potential in terms of cost cutting, management, strategic positioning and quality of earnings".
It is, however, Royal & SunAlliance which is intriguing the stock market. Its cash hogging attitude has prompted speculation it has a big deal in the pipeline. Figures, due next week, are likely to emerge at pounds 140m against pounds 195m. The shares eased 16.5p to 668.5p.
The market had a lacklustre session, with Footsie ending 71.6 points off at 5,956.7. Supporting shares were unruffled with the mid and SmallCap indices stretching to yet new highs. 3i, the investment group with a strong small companies involvement, reflected the popularity of supporting shares with a 12p gain to 600p. Its latest market offering is Taylor & Francis, where it has around 15 per cent. The specialist publisher is coming to market with a pounds 130m valuation.
Kingfisher was the best performing blue chip, jumping 48p to 1,095p on hopes its Superdrug chain will benefit from a drugs price war. But Alliance Unichem fell 7.5p to 429.5p.
Courtaulds, as PPG Industries of Pittsburgh emerged as a possible counter bidder to the Dutch Azko Nobel group, gained 9p to 473p. Northern Foods, which recently demerged its Express Dairies side, improved 12p to 213.5p as SBC Warburg moved its stance to buy and suggested a 250p target.
Fairey, the electronic equipment group, suffered a 66p fall to 498.5p after a profit warning from chairman Sir Robin Biggam. He said returns from the instrumentation businesses, the group's largest operation, would be "well below" last year's corresponding figures.
Cable & Wireless Communications lost an early gain, ending 9.5p down at 442p as Canada's BCE said it intended to sell its 14.25 per cent interest. Cable and Wireless, up 2 p to 679p on persistent speculation about corporate action, may take up some of the unwanted shares.
Engineer Charter continued to attract bullish comments. The price rose 16.5p to 756.5p as Henderson Crosthwaite joined Panmure Gordon in advocating the shares are cheap.
Wassall, the conglomerate now parading as more of a venture capitalist, hardened to 330p on talk of US investment roadshows. Rolls-Royce, with US presentations almost on the runway, fell 6.75p to 297.75p as Mercury Asset Management sold 4.9 million shares, cutting its stake to15.5 per cent.
Somerfield held at 342.5p. BT.Alex Brown believes benefits from the takeover of Kwik Save could be around pounds 100m. "Strong profit growth and improved visibility of warnings warrant a re-rating," said the investment house, formerly known as NatWest Securities.
Gibbon, the printing ink group, jumped 39.5p to 242.5p as Sun Chemicals produced a 250p-a-share agreed offer. Capitol, a security group, gained 27p to 167.5p after a management buyout materialised at 175p a share. Chemical group Brunner Mond, an original constituent of Imperial Chemical Industries which came to market at a cut-price 175p two years ago, gained 7.5p to 186.5p as a 190p a share offer was accepted from a company called Soda Ash Investments.
The failure of talks at Lambert Smith Howard, the estate agent, had little impact. After falling 22p, the shares rallied on hopes of a hostile strike, ending 2p off at 167.5p. Property Partnership fell 25p to 292.5p as its bid talks were terminated.
Air London, an air charter broker, climbed 17.5p to a 377.5p high with takeover talk intensifying. Celsis International, the struggling drugs group, rose 8.5p to 41p; chief executive Arthur Holden has quit and is talking about mounting a bid (rumoured to be around 60p a share).
ScS Upholstery hardened 4.5p to 143.5p after Merrill Lynch said buy; Uno, accorded the same recommendation, was 1p higher at 240p.
Arriva, the transport group, continued to rally after being hit by a downbeat trading statement and a persistent, now thought to be cleared, institutional seller. The shares rose 13p to 447.5p. They have been as low as 420p. Before they were unsettled by worries over the group's financial side the shares were riding at above 500p.