That's not the case with National Grid, however. Yesterday, the company that maintains electricity pylons around the country watched its share price rise 25.5p - or 7 per cent - to 388.5p, making it the best performing stock in the FTSE 100 index.
This rise, though steep, is not out of character. In the past 12 months, National Grid shares have gained almost 70 per cent in value. But no, it's not speculation that some US giant is lining up a bid to take over one of the few parts of the electricity sector not already in foreign hands.
In fact, National Grid was largely basking in reflected glory yesterday. Because the main driver of its share price rise was the market's euphoric reaction to news that Energis, the telecoms group, had sealed a joint venture with European giants Deutsche Telekom and France Telecom to build local networks in London, Birmingham and Manchester.
Energis used to be part of National Grid until last December, when it was floated off. But National Grid, being a sensible utility, decided to hang on to 75 per cent of the shares. Since then, Energis shares have more than doubled in value - they added another 106p to 665p yesterday - taking National Grid along for the ride.
The Energis announcement had little effect on the rest of the telecoms sector. British Telecom largely shrugged off suggestions that the new joint venture would be a serious competitor in the business market with a 3p slip to 668p.
Colt Telecom, the local network operator which will face more competition from Energis in London, added 2.5p to 1410p.
Investors warmed to Cable & Wireless Communications after the cable operator confirmed savage job cuts as part of a wide-ranging restructuring programme. The shares added 7p to 411.5p.
Mobile operator Orange, with broker SBC Warburg still sitting on a large stake, gave up 5p to 401p even though new subscriber figures were in line with expectations. Broker Dresdner Kleinwort Benson advised investors to switch into rival Vodafone, up 0.5p to 629p.
The market yesterday hit another new peak, adding 35.2 points to 6052.8 as traders shrugged off renewed gloom in Tokyo, which dragged down the Nikkei index. Liquidity continued to flow into the market, while a buoyant start on Wall Street helped London shares in the afternoon session.
But figures from Foreign & Colonial introduced a note of caution. The fund manager pointed out that the first quarter of 1998 was the best three- month period for the FT All-Share index since 1987, and the best for the Footsie since 1992. David Manning, head of UK equities, said: "There is little room for disappointment in the UK market."
Courtaulds was the best performing second-liner yesterday, rising 67.5p to 456.5p as the chemicals group revealed that it had received a bid approach. Speculation about the identity of the predator settled on Akzo Nobel, the Dutch group, although ICI, unchanged at 1125p was also named.
The news sparked a renewed flurry of interest in the speciality chemicals sector, many of whose constituents are expected to be swallowed up by larger groups in the coming few years. Inspec gained 14.5p to 252p while Laporte was 20p better at 831.5p and Albright & Wilson added 4p to 182.5p.
Directors were out in force buying shares yesterday. TI, the engineering group, added 15p to 552p as Lady Lewinton, wife of chairman Sir Christopher, bought 20,000 shares at 553p.
Sir Brian Pitman, the Lloyds chairman who is also a non-executive director of Next, decided to support the retailer by buying 2,000 shares at 574p. Sir Brian had barely attended his first board meeting before Next announced a massive profit warning which wiped a quarter off the company's values.
However, his support could not revive the share price which slipped 12p to 565p on a sell recommendation from broker HSBC.
Pace Micro Technology, making set-top decoders for televisions, jumped 5p to 51.5p on news that directors David Hood and Robert Fleming had each bought 2.8 million shares at 44.5p. The move gives Mr Hood, one of the company's original founders, a 25.9 per cent stake in the company while Mr Fleming now has 5 per cent.
Security and fire group Williams dipped 8p to 478p after Credit Lyonnais Laing issued a sell recommendation pointing out the group's premium rating, poor cash flow, moderate growth and poor track record in delivering shareholder value.