* Big catalyst for RIM remains the launch of its BB10 line
* Investors will seek clues, new details on BlackBerry 10
* Cash pile, subscriber numbers to draw attention
* Downtrodden share price has doubled since Sept. 24
By Euan Rocha and Allison Martell
TORONTO, Dec 16 (Reuters) - The surprising rally in Research In Motion stock from its September depths shows no signs of waning ahead of next month's crucial launch of the company's BlackBerry 10 smartphones, and the stock could ring up more gains if RIM delivers on a handful of telling metrics in its quarterly report on Thursday.
At this stage, profit and revenue won't matter much for RIM . The company will likely report a third straight quarterly loss, reflecting declining monthly service fees, ebbing device sales and other problems.
What investors want to see are indications of momentum as the BB10 launch on Jan. 30 approaches. The new line is probably the company's last hope of reclaiming market share lost to Apple's iPhone and devices powered by Google's Android operating system.
"The biggest catalyst for the stock by far is a successful BlackBerry 10 launch," said Morningstar analyst Brian Colello. "The entire investment thesis hinges on BlackBerry 10 ... so that is the key focus right now."
With focus on the launch, cash on hand will indicate whether the Waterloo, Ontario-based company has the funds it needs to market its new line effectively.
"I want to see the cash balances retained so that they have lots of availability to support the launch of BB10 in January and February," said National Bank analyst Kris Thompson.
"They are going to need money to build their inventory and to promote the new product on a global launch. It's going to cost hundreds of millions of dollars, so it is pretty important that they maintain that cash balance."
Despite a massive loss in the last quarter, RIM added $100 million to reserves as it slashed costs and cashed in on money it was owed, bringing the total to $2.3 billion.
As a second point of interest, investors will size up any charges RIM books in its fiscal third quarter for layoffs and other aspects of its painful restructuring.
"If it is $100 million or $200 million to finish off the restructuring, I think people probably would be OK with that," said CIBC World Markets analyst Todd Coupland, who has a "sector outperformer" rating on RIM's stock. "Anything beyond that probably is going to be cause for some concern."
Metrics such as service revenue, shipments and subscriber numbers will likely merit attention as well.
The company bucked analysts' expectations last quarter and expanded its subscriber base to 80 million as gains in emerging markets partly offset defections in North America.
"The biggest number is the number of BlackBerry subscribers that they are able to still hold on to during the transition," said Morningstar's Colello. "Investors would like to see that customers are not heading for the exits right before this transition."
Although RIM's stock is well below the heady highs of 2008, the share price has doubled since Sept. 24, fueled by positive feedback on BB10 from developers and telecom carriers, along with a slew of analyst rating and share-price target upgrades.
Even such long-time RIM bears as Eric Jackson, the founder of Ironfire Capital, believe the recent momentum in the stock is unlikely to dissipate in a hurry.
Shares of RIM, hovering just above $6 in late September, closed on Friday at $14.04 on the Nasdaq.
"If they can actually ship a somewhat decent number of units and increase that subscriber base and keep their cash balance near flat quarter over quarter, the stock's going to, I would say, pop even more," said National Bank's Thompson, who has an "outperform" rating on RIM's shares and a $15 price target.
Analysts also hope to learn more about the BB10 devices. Pictures, video and specifications have leaked in recent weeks, but investors hope RIM offers up more juicy details during its quarterly conference call after the results are released.
Thompson wants to know when shipments are going to be commercially available, pointing out that Jan. 30 is only the date for the global unveiling. He is also eager to find out when RIM will start selling a device with a traditional keyboard, as the initial model rolled-out will be a touchscreen only.
"All we know is it's 'shortly after' the virtual keyboard, but I am not really sure the dictionary defines what 'shortly' is, so we want to have some concrete timelines," he said.