The news that Holcim and Lafarge are planning a merger should come as no great surprise to long-term observers of the industry. Such mega-mergers have been periodically mooted over the decades and have already come to pass.

Lafarge took its present form through many acquisitions, but it was the mega-merger with Blue Circle Industries that brought it to pre-eminence. That deal was hard fought, rapidly becoming a hostile takeover after the then-CEO of Blue Circle, Richard Haythornthwaite, decided that the amount that the CEO of Lafarge, Bertrand Coulomb, was offering for his company was not high enough.

A year of claims, counter-claims, offers, rebuffs and haggling ensued, leading to a higher offer that was eventually accepted by the Blue Circle board. However, as Lafarge was a Euro-denominated company and Blue Circle was resolutely British (and was thinking in UK pounds sterling) after exchange rate variations had been taken into account, Lafarge paid less after a year than it had offered in he first place. The British CEO got a big pay-off and went on to greater glory, having appeared to extract a great deal more money (in GB pounds) for his shareholders. Apparently they teach this as a case study in business schools.

Mega-mergers have also shaped other giants in the industry. For example Chichibu-Onoda and Sumitomo-Osaka came together to make Taiheiyo Cement and Ciments Français was added to Italcimenti, although in this last case they still retain their separate identities. Often the deals amount to an accretive takeover by one larger company of a smaller one, but transformative deals consisting of a 'merger' of 'equals' also happen in the cement industry, and with good reason. The merging of research efforts; the optimisation of management; the rationalisation of procurement strategies: all of these will immediately save plenty of money.

However, it's on the financial side that these larger merged companies can sometimes see the most benefit. The cost of borrowing money is inversely proportional to the size of the company (and of the sums involved); the colossal sums demanded by overpaid and greedy bankers will diminish in proportion if the sums involved are larger. So, the cost of borrowing money to be able to invest in takeovers or for capital expenditure will reduce as a proportion of overall cost.

There are other significant potential savings as well, from operational synergies, although these can be harder to quantify and - critically - harder to retain once the competition technocrats have run their slide rules over the proposed deal. They generally do not like too much of the market ending in the hands of too few players.

A good case in point is the recent mega of Tarmac and Lafarge in the UK. To allow the deal to take place the merged company was obliged to sell off one of its key assets, the Hope cement plant, which is now owned and operated by newcomer Hope Construction Materials. Even after the deal has been completed, the market regulator is considering the possibility of making the merged company sell additional facilities, something that strikes Global Cement as 'just not on.'

However, with operations in 90 countries, Lafarge and Holcim can expect to face competition scrutiny in at least 15 countries including Brazil, Canada, Ecuador, France, the UK, the US, Morocco and the Philippines. Meanwhile, in Serbia it has been reported the two companies have a combined market share of 97% across all their business lines!

Lafarge and Holcim have overlapping facilities and distribution networks in a number of countries, and any merged company will probably be required to sell some of them to its competitors. Other companies might be licking their lips at the prospect, as usual CRH is already being lined up in the Irish press, but the units will be sold at a market rate - and not a penny less. It might be that the merged company cannot control which facilities are sold, meaning that they might end up with a less than optimised system. Not so good after all.

If the deal goes through, it will create a Europe-based behemoth with a production capacity of over 200Mt, enough to retain a place on the global top 10 companies with the ever-rationalising and concatenating Chinese companies. When the news first broke we asked what might the new company called? We liked a short mash-up of the two names, like Lolcim (a humorous nod to today's 'youth-speak' perhaps) or Hafarge. However, the level of preparation backing the merger plan soon became clear from financial due-diligence right down to a new name: LafargeHolcim.

Yet for all this co-ordinated work from companies that were meant to be competitors until as recently as March 2014, we should remember what happened to the proposed BHP Billiton-Rio Tinto takeover. Valued at a high of US$170bn it shrivelled up as the global economy collapsed in 2008 amidst concerns from regulators. The idea may be out there but LafargeHolcim has a long way to go before it actually exists.