The cash-and-stock offer follows multiple refusals by Macerich to discuss a possible deal, which has enterprise value of $22.4 billion including debt, Simon said on Monday. Macerich shares rose as much as 7 percent to an 8-year high of $92.43, brushing past Simon’s offer of $91 per share. A combination of Indianapolis-based Simon and Santa Monica, California-based Macerich could boost their ability to negotiate leases with store owners at a time when mall operators are experiencing a fall in traffic as consumers take to shopping online, which is more convenient and often cheaper.