At the close, OMXS rose 0.8 percent.
On the OMXS30 large-cap list, Skanska was at the top, up 2.4 percent. Evolution was at the bottom, down 1.1 percent.
The Swedish stock market got a boost when the Swedish Supreme Court's customs decision was announced at 4 p.m.
There were also gains in Europe at the end of the trading day. The stock exchanges in London, Paris and Frankfurt all closed in the green.
During the morning, both the Tokyo and Hong Kong stock exchanges fell, while the stock exchanges in mainland China remained closed for the weekend. Wall Street jumped higher in the wake of the tariff announcement, which followed fresh figures of unexpectedly high inflation.
The oil price fell back slightly during the afternoon and a barrel of Brent crude was trading at just over $71.
