Kaneohe Ranch and the Harold K.L. Castle Foundation’s holdings of more than 60 properties are expected to sell for as much as $600 million.

The properties on about 600 acres that include most of Kailua’s retail center are being offered as one or two packages — splitting the mainland and Hawaii assets — and will likely fetch a combined price in the mid-$500 million to low-$600 million range, according to a source close to the deal who asked not to be identified.

Assets listed in a confidentiality agreement obtained Monday by the Star-Advertiser include 52 Kailua, Kaneohe and townside properties as well as nine mainland holdings.

The real estate includes shopping centers, land leased to businesses and the 38-acre retail center of Kailua. The properties are being offered to select investors by the brokerage firm Eastdil Secured.

Kailua residents and business owners are concerned about the future of the small beach town, which has remained relatively free of large-scale development.

Kaneohe Ranch has "pretty much tried to keep Kailua Kailua, like what it was before," said Rusty Niau, 59, who was raised in the area and has lived there for about 40 years. "If they sell it, who knows what will happen. Is Kailua going to turn into another Waikiki?"

Others fear that a new owner might not be as friendly to many of the small businesses scattered throughout Kailua’s commercial center.

"I’m scared if it’s a mainland company coming in," said 63-year-old Jack Aaron, president of Aaron’s Dive Shops, which has leased space from Kaneohe Ranch for about 35 years. "The one thing about Kaneohe Ranch is they definitely employ local people, and they seem to really care about the tenants and the properties they manage. Will new management be going to want to raise rents a lot and change the way things are? The fear with new people is if they’re all from the mainland, then you’re going to have that mainland mentality."

Mitch D’Olier, president and chief executive officer of Kaneohe Ranch Management Ltd., wouldn’t comment Monday beyond an earlier statement that said a transaction would not affect efforts of the Castle Foundation — Hawaii’s largest locally based private foundation — which "will continue to play a key role in the community."

Kaneohe Ranch, which produced a long-range plan for Kailua in 2004 based on extensive community input, has invested more than $35 million in improvements that included new shops and restaurants in recent years while trying to maintain Kailua’s character. Some are worried that a new owner might have its own vision for the town.

"Whoever the landlord is, it’s important that they keep in mind the desires of the community residents as well as the necessity to have a thriving business community and to create a balance that kind of maintains a harmony in town," said Bob Twogood, who has run Twogood Kayak Hawaii Inc. for 32 years in Kailua.

Todd Di Antonio, a small-business owner who has lived in Kailua for more than 15 years, added, "Kailua is its own special little market on this side of the island as far as businesses go, and we tend to stay in this part of the island. We’re kind of self-contained to a certain extent. I’ve got concerns if for some reason it was a foreign entity. Hopefully they’re not going to sell to somebody of a foreign influence that wouldn’t be good for the community."

A new owner may have an opportunity to redevelop much of Kailua’s commercial core because several land leases are set to expire within the decade.

"We don’t want to change the character of Kailua," Niau said. "We’d like to keep Kailua as much country as we can. It is a unique town. That’s part of the beauty. At any point in Kailua you can look up and see blue skies. I don’t want to be stifled or closed in by high-rises."