The Simon Property Group, the Indianapolis-based owner and operator of shopping malls, announced on Friday that it planned to spin off its strip centers and smaller enclosed malls into a real estate investment trust.

The spun-off REIT will consist of 54 strip centers and 44 malls in 23 states. They include Brunswick Square in East Brunswick, N.J., Seminole Towne Center in Orlando, Fla., Great Lakes Mall in Cleveland and Bowie Town Center in Bowie, Md. The strip centers have an occupancy rate of 94.2 percent, while the enclosed malls have 90.4 percent occupancy. Strip centers account for a little more than 3 percent of the overall business of Simon Property, the biggest mall owner in the country.

Simon Property estimated that the spinoff’s portfolio would generate net operating income its first year of $400 million. The new company would have $2 billion in debt, representing a ratio of net debt to earnings before interest, taxes, depreciation and amortization of about 5 to 1.

Shares of Simon Property were higher in premarket trading.

Richard S. Sokolov, Simon Property’s president and chief operating officer, will be chairman of the spun-off company, while David E. Simon, the chairman and chief executive, will serve as a director. The distribution of shares to Simon Property shareholders is expected to be completed in the second quarter of 2014.

“This transaction allows Simon to focus on our global portfolio of larger malls, Mills and Premium Outlets while maintaining our considerable scale and conservative leverage profile,” Mr. Simon said in a statement.

Bank of America Merrill Lynch and Goldman Sachs are advising Simon Property, while Wachtell, Lipton, Rosen & Katz is serving as legal adviser.