"Profitability is heavily dependent on our maintaining sales at near last quarter's level," the memo said.

It maintained high sales for the following two weeks and sold a total of 173,115 copies in 2006.

It then failed to maintain sales, and kept dramatically falling, spending only 9 weeks inside the national top 50.

His advice: Buy smaller companies with product cycles that can maintain sales through an economic downturn.

Cars became steadily larger and more elaborate as manufacturers sought to maintain sales.

The company continued to produce catalogues, and maintained sales of a few hundred homes per year through the 1960s.

So has the high cost of maintaining extensive sales forces.

The over-55s, who reportedly eat more chocolate than children, now help to maintain sales.

Gulfstream's new president believes he can maintain sales despite declining military and corporate spending.

"Until then, though, I'd still be cautious because I don't know how much more they will have to reduce their margins to maintain sales."