In a move designed to make money, said the “Sage of Omaha”, legendary investor Warren Buffett has offered to underwrite $800 billion (£400bn) of U.S. municipal bonds.

The offer goes to three “monoline” bond insurers, Ambac Financial, MBIA and Financial Guaranty Insurance. One has already rejected the deal, and he is still awaiting reponses from the other two, although one of them is making favourable noises.

The move certainly perked up global stock markets yesterday, as the monolines are seen as the second line of defence against the sub-prime mortgage fiasco by propping up banks’ balance sheets in the event of meltdown.

Traditionally, the bond insurers mainly concentrate on municipal risk, but they too got caught up in the collective madness of sub-prime lending for the same reason respectable banks did : greed for perceived easy money.

However, the monolines are now short of capital and are being hit by downgrades from the rating agencies.

T J Marta, fixed income strategist at RBC Capital Markets, said it was a coup for bond insurers, which could help them avoid “the doomsday scenario”.

Let us hope so.

In the UK, shares included in the FTSE 100 are around 5pc down on an April high. However, The Financial Mail is following a stategy that counters this trend:

The Dogs of the Footsie approach is based on a theory conceived by American fund manager Michael O’Higgins. We buy shares in the ten Footsie companies with the highest percentage yield — their predicted annual dividends divided by current share price.

Then, every three months or so, we check to see how the list of top ten yielders has changed. Companies might drop out because their share prices have risen or forecast dividends have been cut ; and they might move into the top ten if dividend forecasts have increased or their share prices have fallen.

We sell shares in the companies that drop out and reinvest that money equally in companies that have moved into the top ten.

In assessing the performance of our investments, we look only at share price. We do not take into account dividend income received.

Since the Mail’s portfolio was launched in 2001, the Footsie 100 has risen about 4pc, so an investment of 10,000 units would now be worth 10,400 units.

On the same basis, however, the Mail’s portfolio would be worth 17,493, a gain of almost 75pc.

It seems like Dogs really do run faster.

LSE Latest reports that The New York Stock Exchange has signed a $20 billion (£10.7 billion) merger agreement with Euronext, the conglomerate of European exchanges, in an historic deal to create the world’s biggest stock exchange.

The combined business will become the world’s first transatlantic exchange: NYSE Euronext, at a ceremony in Paris this afternoon, chosen to demonstrate that it’s a merger of equals, not a takeover.

However, Thomas Caldwell, whose company owns 4.3 million NYSE shares, told The Times (London) that “the international nature of the deal might fall foul of politicians worried by foreign takeovers of key US businesses”.

John Thain, NYSE chief executive, will become CEO of the proposed combine, the headquarters of which will be on Wall Street. Jan Michel Hessels, Euronext’s supervisory board chairman, will be the new chairman.

A Euronext spokesman said: “The balance of the executives will be maintained.” A Euronext director could take over the CEO role when Thain retires, he implied.

NYSE and Euronext shareholders must still vote on the merger.