After last week's decline, the American stock exchanges turned upwards again on Monday.
The broad S&P 500, industrially oriented Dow Jones, and Nasdaq's composite index all closed 1.2 percent up.
Apple presented news about, among other things, the new model of iPhone and Apple Watch. Investors received the news with some caution, the stock closed unchanged.
For other tech giants, it went better. Microsoft rose 1.0 percent, chip manufacturer Nvidia increased 3.5 percent, while electric car manufacturer Tesla went up 2.6 percent.
Aircraft manufacturer Boeing lifted 3.4 percent since the company reached a preliminary agreement with the largest trade union at Boeing. If the agreement becomes definitive, a strike that would threaten to stop aircraft production later in the week is avoided.