Rigetti Computing (RGTI 2.83%) surged ahead to close up 15.5% Wednesday after investment bank Cantor Fitzgerald initiated coverage of the quantum computing stock with an outperform rating (i.e., buy) and a $15 price target -- which, if correct, implies Rigetti stock could go up another 20% over the next 12 months.

Image source: Getty Images.
Quantum investing
"Quantum computing is in its infancy," explains Cantor in a note covered on StreetInsider.com today, "but remains one of the most highly coveted technical milestones with enormous economical implications."
Rigetti is a small fish in this still-small pond, sharing the water with megalodons like Alphabet, IBM, Intel, and Microsoft. But as Cantor sees things, this isn't necessarily bad news for Rigetti, which might "benefit from the efforts of other," larger companies, to advance the technology, notes The Fly.
Is Rigetti Computing stock worth buying?
And yet, this all seems pretty speculative. Cantor itself confides: "We are likely years away from full-scale quantum capabilities," and admits Rigetti, which has only $9 million in annual revenue (and no profits) to back up its $3.6 billion market capitalization, trades at a "steep" multiple to "any near-term revenue or earnings forecast."
That's putting it mildly. Rigetti stock actually sports a nosebleed price-to-sales ratio of 273, and costs infinity times the earnings it doesn't have. Momentum investors like Cantor might still drive the stock higher, but most analysts don't see the company turning profitable, ever -- or at least not before 2030, which is as far out as estimates go.
Buy the stock anyway if you like. But do realize that in doing so, you're gambling, plain and simple, and not investing at all.