The broad S&P 500 index rose 0.3 percent, Nasdaq's technology-heavy composite index climbed 0.5 percent and the Dow Jones industrial index added 0.2 percent.
Nvidia acted as a locomotive, up 2.1 percent, after declines last week.
American gaming giant Electronic Arts surged 5 percent on the news that the company will be bought out from the stock market in the USA by a collection of venture capital companies and the Saudi development fund PIF.
The price tag, $210 per share, a total of approximately 500 billion kronor, makes the deal the largest so far when it comes to buyouts from the stock market.
In the USA, it's starting to get urgent to agree on the state budget (October 1), otherwise shutdowns in the state apparatus are threatening again.
The oil price has continued downward on Monday. A barrel of North Sea oil now costs less than $67.
