Shares of shopping-mall landlord Macerich Co. rose to their highest price in more than three months last week after the Wall Street Journal reported that Simon Property Group Inc., the largest U.S. mall owner, had made approaches to buy the company.

Macerich, of California, agreed in July to invest $107 million in the Gallery at Market East in Center City in a joint venture with owner Pennsylvania Real Estate Investment Trust. In the Philadelphia region, Simon owns nine malls, including those in King of Prussia.

Simon made the takeover approach in the last few weeks, after a previous overture late last year, the Journal reported, citing people familiar with the matter. A formal offer for Macerich has not been made, the report said.

In November, Simon said that it had accumulated a 3.6 percent stake in Macerich, and that it might try to buy more, sparking speculation of takeover plans. At the time, Simon said it might seek to have the real estate investment trust waive a provision that restricts ownership to 5 percent.

A purchase of Macerich, which has a high concentration of West Coast properties, would increase Simon's reach nationwide.

The reason Simon would go after Macerich is to get "access to a portfolio of malls that otherwise they have no way of getting," said Jeffrey Langbaum, real estate investment trust analyst for Bloomberg Intelligence. "The higher-quality mall REITs have to be creative to find acquisitions because there is not a lot out there for sale."

Macerich shares have gained 26 percent since Simon disclosed its stake Nov. 19, giving it a market value of about $13.9 billion.

Les Morris, a Simon spokesman, declined to comment on the Journal report. A voicemail left for Thomas O'Hern, Macerich's chief financial officer, was not immediately returned.

Simon has been developing outlet malls around the world while refurbishing and expanding some of its biggest U.S. properties to boost growth.

The company has become the biggest U.S. REIT, with a market value of about $59 billion, in part by making acquisitions and entering joint ventures. Last month, Canadian retailer Hudson's Bay Co. said it agreed to contribute 42 properties to a retail venture with Simon that will be valued at $1.8 billion.

Simon also has been active in transactions outside the U.S. In 2012, the company acquired an interest in European mall owner Klepierre, based in Paris.

Simon failed in an effort to take over General Growth Properties Inc. after the second-largest mall owner filed for bankruptcy in 2009. General Growth exited bankruptcy in 2010.

Before Simon's share purchase disclosure last year, Macerich said it had bought the share of five U.S. shopping malls it didn't already own from a subsidiary of the Ontario Teachers' Pension Plan Board for $1.89 billion, including debt.

The purchase price included $1.22 billion of stock issued to the pension plan, or an ownership of almost 11 percent.