Shares of a global snack company Kellanova (K 7.69%) are soaring on Wednesday, just over a week after their last run. Normally, this is a fairly quiet stock, but today a rumor was confirmed: Mars plans to buy the company for $35.9 billion. And that’s why Kellanova stock was up nearly 8% at 10:30 a.m. ET.

An irresistible offer

In October, the Kellogg Company spun off its North American cereal business and WK Kelloggand the remaining brands and regions became Kellanova. Management said this would create a higher-growth snack business that was more attractive to investors. And apparently it was attractive to privately held Mars, too.

Mars – parent company of snack brands such as Snickers and Skittles – intends to acquire Kellanova for $83.50 per share. At the time of writing, that represents about 4% upside potential for Kellanova stock.

RBC Capital analyst Nik Modi had previously suggested that Kellanova could be worth $108 per share if acquired – nearly 30 percent more than the current takeover price. However, I believe Mars is being generous. Its offer is almost three times Kellanova’s revenue. That’s a fair price for a food company with modest growth.

What should shareholders do now?

Let’s make it simple. Here are the two most likely outcomes: the deal will go through, or it won’t. As for the first possibility, it may take some time. And when it does, the stock only has about 4% upside left. Shareholders should ask themselves if that’s enough for them to hold on to the stock now.

Shareholders should keep in mind that Kellanova stock is currently trading at an all-time high, about 40% above its recent average, so if the deal falls through for any reason, I think we can expect a short-term decline in Kellanova stock.

I think it makes a lot of sense to sell Kellanova shares now and reinvest the money elsewhere.