Nasdaq is increasing the fees it charges listed companies, sending a frisson of fear through users of the London Stock Exchange.

British companies are now wondering whether Robert Greifeld will use a fee hike to recoup costs if Nasdaq takes over the LSE. Fees at the American exchange rose by 22pc for smaller companies and 27pc for larger ones.

On Nasdaq, annual fees start at £16,000 ($30,000) rising to £51,000 ($96,000). In London, the equivalent range is £3,600 ($6,768) to £35,000 ($66,000).

Anatole Kaletsky of The Times (London) reminds us that “the financial hurricane season” is now upon us : “Nearly all the greatest financial accidents — the Wall Street crashes of 1929 and 1987, Nixon’s closure of the Bretton Woods gold window in 1971, the Asian currency crisis of 1997, the Mexican and Russian defaults, the attack on the French franc in 1993, the sterling devaluations of 1949, 1976 and 1992 — have occurred between late August and October”.

In the UK, the old stockbrokers’ maxim of ceasing to buy between May and the St Ledger (September 9 this year) is usually a stable guide to events (pun intended).

On Wall Street buyers generally hold off until Hallowe’en, on October 31, while selling is automatic for various reasons : “…selling of equities is partly a passive phenomenon, since portfolios have to be liquidated when their owners die or cash retirement cheques or make insurance claims.

“These liquidations happen steadily through the year, regardless of seasons. Buying, on the other hand, requires conscious decisions and investors are less likely to make these when they and their brokers are away on holiday.”

Given that September clears the way for the start of The Great Consolidation Season, in which Nasdaq is able to mount a full-scale bid for the London Stock Exchange, it should be an interesting time.

But do consolidation and hurricanes have much in common? We shall see.