What happened

MongoDB (MDB -1.53%) stock is rocking in morning trading on the Nasdaq, up 6.5% as of 11:55 a.m. EDT.

You can thank Goldman Sachs for that.

A green arrow rises upward.

Image source: Getty Images.

So what

This morning, the megabank announced it is initiating coverage of the database platform stock with a buy rating and a $310 price target that implies there's another 19% upside on top of today's gains.

Why? As Goldman explains in a note covered on StreetInsider.com this morning, with "Atlas momentum [driving] durable growth with strong competitive positioning and developer mindshare ... MongoDB is well positioned to capitalize on growth from net new workloads and replatforming of legacy applications."

Goldman predicts that MongoDB will enjoy "durable, sustained growth over the medium-term," yet its stock price is down 42% since February, significantly underperforming the broader tech stock space, and leaving MongoDB stock "trading at a 16% discount to broader SaaS peers."

Now what

It's not entirely clear on what basis Goldman is making that comparison. MongoDB, after all, has never earned a profit -- and indeed, its losses are mounting, with last fiscal year seeing a net loss of $267 million, and no free cash flow, either.

The company sells for a 27 price-to-sales ratio. That may be cheaper than its "SaaS peers" -- but it's far from cheap.