PepsiCo and Anheuser-Busch are responding to straitened times by clubbing together.

The two drinks companies have joined forces to get better prices for anything from buying paper clips to shipping drinks around the U.S. The deal promises some of the benefits of a merger, without the inherent risks. Others will be watching carefully to see what savings the two firms can eke out.

It’s easy to see the appeal. Pepsi’s selling, general and administrative expenses totalled $15.9 billion in 2008 while Anheuser-Busch InBev — the parent of Anheuser-Busch — spent $5.26 billion on global administrative, distribution and sales and marketing expenses in 2008. Shaving just a few percentage points off these costs would translate into huge benefits for the bottom line of both companies.

The co-operative purchasing arrangement won’t encompass all of these costs: it applies only to the companies’ back office — mainly U.S. goods and services not directly related to the drinks they sell. Nevertheless, it will still be a worry for suppliers who face the prospect of far tougher negotiations with a combined procurement team.

These providers may squeal, but the Federal Trade Commission tends to use a very narrow definition of what constitutes a market and since Pepsi and Bud don’t compete directly they seem unlikely to get a hard time from regulators.

The spoils are obvious. Estimates vary, but in the retail sector some half to two-thirds of planned synergies from a merger generally come from purchasing savings. There’s no way Pepsi and Anheuser will achieve anything like this, but if they can keep the administrative costs down then the savings they can make in non-core areas — including technology hardware, office supplies and transportation — should give them both a competitive advantage over their nearest rivals Coca-Cola and SABMiller.

The companies know each other already. Anheuser-Busch InBev bottles Pepsi in areas such as Brazil. SABMiller, the world’s No 2 brewer, has a similar deal with Coke in South Africa. This is proof that there are synergies to be found between beer and soft drinks makers.

The plan is not without risks. Firstly, the move will undoubtedly antagonise suppliers. Secondly, the longer and more entrenched such a relationship, the more inter-dependent the two parties become. Disentangling themselves could be costly.

Even if the savings on each contract are modest, the risks seem worth taking for Anheuser and Pepsi. The overall effect could be significant at a time when companies are all vying to squeeze costs out of their businesses. Rivals should pay close attention.