Before shareholders of Public Storage Inc. break out the champagne to celebrate the $5 billion purchase last week of Shurgard Storage Centers Inc., they may want to wait to read the fine print on the costly merger.

For starters, analysts are questioning why Public Storage agreed to pay a hefty 39 percent premium above Shurgard’s stock price last July, before the bid was announced.

David Harris, an analyst at Lehman Brothers, asked in a conference call last week why the company agreed to pay so high a price.

“I just wonder why you feel it’s right to pay this sort of price when a lot of transactions don’t appear to be quite so aggressively priced as this?” Harris asked Ronald Havner Jr., Public Storage’s president and chief executive.

Havner’s response: “Both organizations know the self-storage industry extremely well, and both companies have concluded that (the payment is) an appropriate consideration.”

Havner refused to comment on whether the Shurgard acquisition will be accretive to Public Storage’s 2007 cash flow.

It will take weeks before Public Storage files documents with the Securities and Exchange Commission outlining how much it has paid its investment banker, Goldman Sachs & Co., and legal counsel, Wachtel, Lipton, Rosen & Katz, who were instrumental in putting plans in place to get the deal done.

The fees are likely to be hefty considering David K. Grant, Shurgard’s president and chief executive, will walk away with $130 million once the deal is approved. Analysts expect the company will eliminate Shurgard’s Seattle headquarters, which has 200 employees.