Just 5 percent of global telcos control about 62 percent of industry revenue, according to analysts at Booz and Company. One might argue those figures show a high degree of industry concentration. But Booz says there’s significantly more to come.

In fact, “the telecom sector remains relatively fragmented,” Booz consultants say. In the healthcare and oil and gas sectors, companies in the top 5 percent generated 79 percent of total 2009 industry revenue.

International revenue provides another indication that further consolidation is possible. In the telecom business, international revenue accounted for only 25 percent of telecom industry revenue in 2008. That’s well below the 38 percent that all industries averaged, and only half that of some industries, Booz and Company consultants say.

Since 1989, the pharmaceutical industry saw consolidation of more than 30 large companies into just five major competitors.

Consolidation will mainly occur in three ways. Operators will pursue scale through cross-border mergers and acquisitions, entering new markets by making large transactions.

They’ll bolster their competitive advantage through transactions in markets where they already operate. Up to this point, in-country acquisitions have driven the bulk of activity. But in-country consolidation tends to raise regulator market concentration issues.

For that reason, some might predict more growth for trans-border deals.

And telecom operators will also consolidate ownership, gaining full control of operations where they currently have only a partial stake.

For the immediate future, cross-market “megadeals”— transactions in which major telecom operator groups acquire controlling stakes in other groups that have a presence in multiple markets, are likely to be the main trend.

Large international transactions have advantages. They let operators complement their footprint in regions where they already have a presence, or augment their business by entering promising new markets.

Large transactions involve just about as much overhead as small transactions, so large carriers might as well look to large acquisitions.

Large multi-market transactions also allow operators to enter into multiple markets with a single stroke, thus eliminating the complexity, cost and time lag involved in identifying and completing multiple transactions.

Large transactions offer a competitive advantage, enabling operators to preempt other providers from acquiring increasingly scarce and attractive targets.

The point is that the trend of mergers, which has been a feature of the business for some decades, is far from finished.