A big AI and robotics idea that has attracted Walmart and Softbank

Venture-capital giant Softbank notched a $15 billion-plus gain on its 2016 deal to buy Arm Holdings when the artificial intelligence-enabling semiconductor firm went public last month. But not as many investors know about Softbank’s “other” big AI investment, Wilmington, Mass.-based software and robotics maker Symbotic, which Walmart has taken a big stake in itself.

That may soon change.

Symbotic, a company that has already generated market heat selling AI-powered robotic warehouse management systems to clients including Walmart, Target and Albertson’s, is partnering with Softbank to play in a potentially giant and…