Two debt-rating analysts who follow bonds issued by WakeMed and Rex Healthcare say that they won't automatically reduce WakeMed's rating if the hospital borrows millions more to pay for its proposed $750 million purchase of Rex.

"As part of the acquisition, there will be certain economies of scale, certain efficiencies that get realized," said James LeBuhn, a Chicago-based analyst with Fitch Ratings. "We would take that into account vs. the increased debt load. There's a benefit to size and scale."

Since WakeMed announced its hostile takeover offer this month, critics have questioned whether the hospital can afford to pay that much money for Rex, plus assume Rex's $158 million in debt. UNC Health officials have said they're not interested in selling Rex, but will form a committee to consider a formal offer from WakeMed.

WakeMed officials, including Tom Oxholm, an accountant who took over as chairman this week, have said they will pay for Rex using a combination of more than $600 million in cash reserves as well as additional financing.

"That is a staggering amount of money," said Kevin Schulman, a health-care economist at Duke University. 

According to the city's public-information office, Standard & Poor's, Fitch Ratings and Moody's Investors Service have reaffirmed Durham's AAA credit rating -- the best that it can be in the eyes of the three main credit-rating firms.