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Here are five things you must know for Tuesday, Sept. 12:

1. -- U.S. stock futures were rising Tuesday, Sept. 12, and global shares traded mostly higher following strong gains during the previous session as Hurricane Irma weakened and recovery efforts began, particularly in hard-hit Florida.

The S&P 500 rose 1.08% on Monday, Sept. 11, to a new record at 2,488.11. The Dow Jones Industrial Average finished up more than 250 points, or 1.19%, and soared above 22,000 for the first time since Sept. 1. The Nasdaq jumped 1.13%.

The S&P 500 and the Dow both enjoyed their largest gains in six months, according to data from FactSet.

Insurers and travel companies traded higher on Monday as Irma's preliminary damage wasn't as devastating as some had predicted.

The economic calendar in the U.S. on Tuesday is light, with only the Job Openings and Labor Turnover Survey for July at 10 a.m. ET. The focus on Tuesday likely will be on the technology sector, with Apple set to unveil its new iPhone.

2. -- Apple Inc. (AAPL) - Get Report is expected to unveil three new iPhone models on Tuesday. Here's what we know so far about the big event, which is scheduled to begin at 1 p.m.:

One version of the iPhone could arguably be Apple's most important phone for the next several years. That phone is expected to be dubbed the iPhone X, according to Apple news website 9to5Mac, which discovered the information via leaked software code for the new operating system, iOS 11.

The tech giant typically releases two iPhone models at the annual event, but in honor of the smartphone's 10-year anniversary, Apple is planning to introduce a third, top-of-the-line device that's expected to pack in some more advanced features, as well as a higher sticker price. For several months, speculators had anticipated that the highest-end model would be called the iPhone 8, but Apple may have chosen to call it the iPhone X to commemorate the anniversary and to signify its departure (both aesthetically and software-wise) from previous models.

The iPhone X is expected to come with a $1,000 price tag.

Alongside the iPhone X, Apple is expected to release two other phones, including the iPhone 8 and iPhone 8 Plus

Apple also is expected to announce details about the Apple Watch 3. The third iteration of the Apple Watch reportedly include a connection to LTE wireless networks, eliminating the device's reliance on a nearby iPhone with a Bluetooth connection or a compatible Wi-Fi network.

Apple shares were rising 1% in premarket trading on Tuesday.

Jim Cramer shares how you should trade off of Apple's product unveiling:

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3. -- Samsung Electronics Co.  (SSNLF) looked to steal some thunder from Apple on Tuesday by touting the success of its pending Galaxy Note 8 release as the two tech giants squared off in what could be their most important battle for global smartphone dominance.

Seoul, South Korea-based Samsung said pre-orders for its flagship Galaxy Note 8, which will hit stores Friday, have topped 650,000 and have steamed well past the demand recorded for Samsung's ill-fated Note 7 release last year, despite what some consider to be a hefty price tag that approaches $1,000 for even its cheapest version.

Samsung's update, and indeed the sales debut Friday for the Note 8, appear timed to establish a foothold in the sector's news cycle amid Apple's gala product launch later Tuesday in Cupertino, California. 

4. -- Equifax Inc. (EFX) - Get Report , the consumer credit-reporting company, now faces a reckoning over its own debt rating. 

Standard & Poor's said late Monday that it changed the outlook on Equifax's credit rating to negative from stable after the Atlanta-based company's disclosure that data were stolen on as many as 143 million consumers, one of the biggest cybersecurity breaches in U.S. history. 

Equifax's BBB+ credit rating could be lowered if costs to address the internet attack mount or if the company's revenue declines as a result of the incident, S&P said in a statement. The score also might fall if further weaknesses are revealed in Equifax's internal controls. 

"With substantial litigation expected and potential fines, as well as uncertainty surrounding costs to remediate and possible strategy shifts, we expect that debt leverage could remain elevated," S&P said.

Equifax fell 1.3% in premarket trading Tuesday, following a decline of more than 8% on Monday.

5. -- Irma weakened to a tropical storm on Monday after battering Florida with strong winds and floods that at left about 13 million people in the state without electricity.

The fate of the Florida Keys, where Irma rumbled through as a Category 4 storm, remained largely a question mark, according to the Associated Press, as communication and access to the Keys were cut.

"It's devastating," Florida Gov. Rick Scott said after taking a fly-over of the Keys on Monday.

A Navy aircraft carrier was due to anchor off Key West to help in search-and-rescue efforts, the AP reported. Drinking water supplies in the Keys were cut off, fuel was running low and all three hospitals in the island chain were closed. The governor described overturned mobile homes, washed-ashore boats and rampant flood damage.

Irma moved into Georgia and South Carolina on Monday but still packed winds of 50 mph, causing flooding and power outages.

Updated from 6:02 a.m. ET

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