Shares of uranium giant Cameco (CCJ -1.94%) popped 21.7% in May, delivering their best month yet in 2024, according to data provided by S&P Global Market Intelligence. The stock hit a 52-week high on May 31.

Interestingly, Cameco stock fell sharply on the last day of April after reporting an 8% year-over-year drop in revenue and a large loss for the first quarter. But there's more to the nuclear energy stock's numbers than meets the eye. With the U.S. government also making a big move last month that should favor Cameco, investors didn't leave any chance to bet on the uranium stock.

Investors are betting big on a ban on Russian uranium imports

In mid-May, President Joe Biden signed the Prohibiting Russian Uranium Imports Act into law, banning the import of uranium from Russia, effective Aug. 12.

It's a big move since the U.S. imports the bulk of its uranium fuel to power nuclear reactors that produce nuclear energy, with Russia supplying 24% of America's uranium. The ban will also free up $2.7 billion that would have otherwise gone toward imports. The U.S. government will spend the money to ramp up local uranium fuel production to ensure that the ban doesn't hit utilities and power supply in the nation. As one of the world's largest producers of uranium fuel, Cameco could be a key beneficiary under the act, which explains why its stock price rocketed last month.

Is Cameco stock a buy now?

Cameco's first-quarter numbers released on April 30 disappointed investors. The company's revenue dropped 8% year over year, and it incurred a net loss of $7 million versus a net profit of $119 million in the year-ago quarter. Cameco's numbers, however, were partly because of losses from Westinghouse Electric, a nuclear services company in which Cameco bought a 49% stake last November. Cameco's core uranium segment reported a 34% growth in net earnings because of higher uranium prices in Q1.

Cameco's production is on track with its 2024 plan and it expects to generate $2.8 billion to $3 billion in revenue in 2024, up from $2.6 billion in 2023. The company is also extending its Cigar Lake mine's life to 2036 and evaluating the potential to increase production at McArthur River Key lake mine. The two are among the company's largest mines.

Ultimately though, Cameco is still a commodity stock, which means its fortunes depend a great deal on uranium prices. While there's no denying that the Russian ban will boost the U.S. uranium industry, there are a lot of "ifs" and "buts," such as waivers for utilities to continue to import uranium from Russia if viable alternative sources aren't available. Put another way, although companies like Cameco should win contracts, there's no clarity yet on how or when Cameco will benefit. Investors may want to keep these factors in mind before betting on Cameco stock, especially after its jaw-dropping 75% run up in the past year.