What happened

Shares of Illumina (ILMN -2.69%) -- the self-proclaimed "global leader in DNA sequencing and array-based technologies" -- are moving higher Tuesday morning, up 9.5% as of 11:15 a.m. ET.

You can thank Barclays Capital for that.

Rising blue and orange stock chart.

Image source: Getty Images.

So what

For 10 long months, you see, British banker Barclays has maintained a steadfast underweight (i.e., sell) rating on Illumina stock, as data from StreetInsider.com confirms. This morning, however, Barclays at long last relented on its pessimism, removed its sell rating, and upgraded the shares to equalweight.

As the analyst explained, the Q4 earnings preview that Illumina released last night has allayed the concerns it had about the business. Indeed, Barclays went so far as to call the company's fundamentals "strong" and declare the shares once again "tradable" at a valuation offering at least a tiny discount to Barclays' $400 price target.

Now what

Is Barclays right to remove its sell rating before official earnings come out? If those Q4 results are as good as Illumina says they will be, it might.

In yesterday's update, Illumina said it enjoyed "another very strong quarter," and promised to report nearly $1.2 billion in Q4 revenue, representing 25% growth year over year. Total shipments, "including record NovaSeq ... NextSeq 1000 and 2000," hit a record in the quarter. And with the wind now firmly at its back, Illumina is predicting that it could earn as much as $4.20 per share in non-GAAP profit this year -- well above the $4.03 per share that Wall Street has been forecasting.  

Granted, even maxing out that profits prediction would leave Illumina stock valued at a staggering 94 times earnings -- and those earnings are "forward" earnings, and pro forma, to boot. Even so, that seems to be good enough news for investors, and today they're buying up Illumina shares hand over fist.