U.S. stocks haven't had a week this strong for months.

-- The S&P 500 and Dow are up 2.9% and 2.7%, respectively, through Thursday-putting both on track for their largest weekly gains since the week ending April 17.

-- The Nasdaq has increased 3.8%, on pace for its biggest gain since the week ending May 8.

After fretting for several weeks about the AI trade, chip makers and related stocks roared back to life. Optimism about a potential deal to reopen the Strait of Hormuz has also boosted stocks, as did a round of strong earnings reports.

Some of the biggest gainers this week were stocks that suffered heavily in July. Optical-networking stocks Coherent and Lumentum-both of which were recipients of an investment from Nvidia this year-rose 27% and 17% this week, respectively, after tumbling sharply last month.