Mergers, homes, and phones gave stocks a boost — their biggest gains in almost two months. Neiman Marcus was sold for $6 billion, and Koch Industries bought an electronics components maker, Molex, for $7.2 billion. Some saw the deals as signs of faith in the economy. Home builders’ stocks were some of the biggest gainers after Hovnanian said home prices are rising and its backlog jumped almost 27%. Apple rose; it’s expected to unveil a new iPhone Tuesday. Apple moved back above $500 per share. All 10 industry groups in the S&P 500 rose. The index gained for the fifth day in a row, the longest since eight days of gains in July.