Here are five things you must know for Wednesday, Sept. 18: 

1. -- Stock Futures Fall as Investors Look to Fed's Decision on Interest Rates

U.S. stock futures fell modestly in cautious trading, as investors focused on the Federal Reserve's interest rates decision expected later Wednesday.

The Federal Open Market Committee meeting, the Federal Reserve's policy-making body, is expected to announce Wednesday it has cut interest rates by a quarter-point for the second time this year. The announcement from the FOMC is expected at 2 p.m. ET.

While markets are pricing in a near-certain reduction of 25 basis points in the central bank's key lending rate, the backdrop of surging global crude prices, slowing world economic growth, creeping inflation, presidential pressure and - most recently - a spike in bank funding markets, paints a complicated backdrop for embattled Fed Chairman Jerome Powell.

In fact, the Fed's New York branch was forced Tuesday to inject more than $53 billion in cash into gummed-up funding markets after overnight borrowing costs surged close to 10%, thanks in part to the hefty burden of primary dealers in taking down nearly $45 billion each day in gross U.S. Treasury bond issuance.

The New York Fed will repeat its overnight repo operation later Wednesday, adding to market jitters as to what Powell and his colleagues are likely to say about future rate hikes, and the unwinding in the month ahead of the Fed's $3.8 trillion balance sheet.

Contracts tied to the Dow Jones Industrial Average fell 30 points, futures for the S&P 500 declined 4.40 points, and Nasdaq futures were down 13.25 points.

The economic calendar in the U.S. Wednesday also includes Housing Starts for August at 8:30 a.m., and Oil Inventories for the week ended Sept. 13 at 10:30 a.m.

Earnings reports are expected Wednesday from General Mills (GIS) - Get Report and Herman Miller (MLHR) - Get Report .

2. -- FedEx Sinks After Shipping Giant Lowers Fiscal 2020 Outlook

FedEx (FDX) - Get Report  sank sharply in premarket trading Wednesday, down 11.87% to $152.73, after fiscal first-quarter earnings at the shipping giant missed analysts' forecasts and the company lowered its outlook for fiscal 2020, citing "increasing trade tensions" and the loss of a major contract with (AMZN) - Get Report .

Adjusted earnings in the first quarter were $3.05 a share, 10 cents below forecasts. Revenue of $17.05 billion was flat with a year earlier and matched forecasts.

"The market is changing as volumes are moving out of the (U.S. Postal Service) and we are in-sourcing more," CEO Fred Smith told investors on a conference call. "Over the summer, these challenges increased somewhat due to the decision to not renew our largest Amazon contract and deepening trade disputes."

"While the Amazon contracts represented only a small proportion of our revenues, the nature of our business is such that near-term profits will be adversely affected since the last bit of volume has significant flow through to the bottom line," Smith added. "However, we have closed additional business to replace this traffic, which is being on boarded, and we are taking out significant costs which were unique to Amazon's requirements."

FedEx said it expects fiscal 2020 adjusted earnings of $11 to $13 per share, below Wall Street estimates of $14.70.

The company said it would implement cost cuts to "match capacity with demand."

Amazon is a holding in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells the stock? Learn more now.

3. -- Adobe Falls on Weak Fourth-Quarter Guidance

Adobe (ADBE) - Get Report  fell 2.09% in premarket trading Wednesday to $278.75 after the software company posted fiscal third-quarter earnings and revenue that beat analysts' forecasts but issued guidance for the fourth quarter below expectations amid disappointing results from its newly acquired marketing software unit.

Adobe, the maker of Photoshop, reported third-quarter adjusted earnings of $2.05 a share on sales of $2.83 billion vs. Wall Street estimates for earnings of $1.97 a share on sales of $2.82 billion.

"While we had strong overall revenue in Q3, our subscription bookings growth for Marketo in the mid-market did not meet our expectations, which is being addressed by increasing our focus and investment on demand generation and inside sales," Chief Financial Officer John Murphy told investors on a conference call. "In addition, there were Analytics Cloud subscription bookings delays with related shortfalls in consulting services bookings and revenue associated with the launch of our new Adobe Experience Platform."

Adobe purchased marketing software company Marketo for $4.75 billion in October 2018.

The company said it expects fourth-quarter adjusted earnings of $2.25 a share on sales of $2.97 billion, below analysts' calls for adjusted profit of $2.30 a share on sales of $3.02 billion.

4. -- Facebook Working With Ray-Ban on Augmented Reality Glasses

Facebook  (FB) - Get Report has partnered with Ray-Ban parent company Luxottica to develop augmented reality glasses, with the goal of having them ready for consumers between 2023 and 2025, CNBC reported, citing people familiar with the matter.

The glasses are internally code-named Orion, and they are designed to replace smartphones, the people told CNBC. The glasses would allow users to take calls, show information to users in a small display and live-stream their vantage points to their social media friends and followers.

Facebook confirmed in late 2018 that it was working on AR glasses. But it has struggled to reduce the size of the device into a form factor that consumers will find appealing, a person who worked on the device told CNBC.

One person familiar with the project told CNBC that CEO Mark Zuckerberg has a strong interest in the glasses, and asked hardware chief Andrew Bosworth to prioritize them.

Facebook is a holding in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells FB? Learn more now.

5. -- Chewy Tumbles After Loss Widens

Chewy (CHWY) - Get Report  fell in premarket trading after the online pet food retailer reported a second-quarter loss wider than a year earlier.

The loss in the quarter was $82.9 million, or 21 cents a share, compared with year-earlier losses of $63.1 million, or 16 cents a share. The most recent second quarter included $43.8 million in stock-based compensation costs.

Analysts had forecast a loss of 11 cents a share on revenue of $1.13 billion.

Chewy went public in June at $22 a share. 

The company said it expected third-quarter sales to come in between $1.19 billion and $1.21 billion, a year-over-year increase of 36% to 38%. Analysts forecast sales of $1.16 billion.

The stock fell 3.87% to $29.08 in premarket trading Wednesday.