Announcing the largest e-discovery deal in some three-and-a-half years, Epiq Systems said earlier this week that it will borrow $100m to acquire Encore Discovery Solutions, a service provider for law firms. (My colleague Nick Patience has the full details on the acquisition.) The rationale is fairly straightforward: Epiq wanted to shore up its presence in the western US, so it reached for Phoenix-based Encore. That sort of geographic consolidation happens all the time – but it rarely happens at the kind of valuation that Epiq is paying in its services play.

Encore had generated some $40m in revenue, according to Epiq, meaning it’s trading at 2.5 times sales. That’s a fairly high multiple for a services shop, which typically have lumpy – and concentrated – revenue. (That goes double for a market like e-discovery that is largely driven by unpredictable events like lawsuits.) Unlike Epiq, Encore didn’t have its own e-discovery software, instead licensing it from other vendors. Clearly, however, the lack of IP didn’t hurt Encore’s price.

More representative of the e-discovery market is probably Unify Corp’s purchase last summer of Daegis. Unify paid $37.5m, or 1.6x sales, for Daegis, which generates about half of its sales from tools and the other half from associated services. But from Epiq’s view, the purchase of Encore sets up a relatively low threshold for a return (it is borrowing at around 3.5%) and adds bulk to a business that has a fair amount of momentum. Epiq said recently that its e-discovery business has posted five straight quarters of growth, finishing 2010 with sales at the unit up 45% to a record $81m.