The U.S. stock market enters Monday’s trading with major indices at all-time highs, and naturally, many individual stocks in the same position. However, experts are increasingly warning about overvalued issues and market bubbles — a theme that likely won’t fade this week.

A number of tech stocks have stolen the spotlight heading into Monday’s trade. Alphabet Inc (NASDAQ:GOOGL) and BlackBerry Ltd (NASDAQ:BBRY) made waves over the weekend, while Tesla Inc (NASDAQ:TSLA) was getting batted around after a Monday morning headline.

Here’s what you need to know going into today’s trade:

Tesla Inc (TSLA)

TSLA stock is down Monday after the company’s shares were knocked down a peg by the analyst community.

Goldman Sachs downgraded Tesla shares on Monday morning, dragging the company down from “Neutral” to “Sell.”

Analyst David Tamberrino says:

“While we believe Tesla currently has a lead relative to OEM peers with respect to vehicle technology adoption, electric vehicle architecture, and (potentially) battery scale, our concerns are more near-term oriented with respect to operational execution on the Model 3 launch, an unproven solar business, and cash needs. Ultimately we see a delayed launch (pushing volume growth out and to the right) and FCF burn rate (necessitating a capital raise before 4Q17) to weigh on TSLA’s shares.”

Tamberrino also worries that the SolarCity acquisition “increased the risk profile of Tesla amidst a business model transition,” and lowered the price target slightly from $190 to $185.

Tesla is coming off a fourth-quarter earnings report during which it was announced that CFO Jason Wheeler would be exiting in April — a surprising move that has drawn a little scrutiny from the investment community.

TSLA shares are off more than 2% this morning.

Alphabet Inc (GOOGL)

Alphabet announced that one of its artificial intelligence products will be available in more of the company’s products moving forward.

Google Assistant will now be available in the company’s tablets, smartphones, computers and smartwatches for anyone using Android 6.0 Marshmallow or higher. It can even be used on smart TV systems such as Nvidia Shield TV and AI car systems.

Google Assistant is Alphabet’s virtual assistant app that competes with the likes of Apple Inc.’s (NASDAQ:AAPL) Siri and Amazon.com, Inc.’s (NASDAQ:AMZN) Alexa. You can use GA for a number of purposes, from general search to checking the weather to playing music.

The move brings Google Assistant to about 30% of all active devices. Google Assistant also is available on Google Allo, Google Home and Android Wear 2.0.

GOOGL shares are up 7% year-to-date.

BlackBerry Ltd (BBRY)

BlackBerry is the talk of tech again as the company over the weekend unveiled the specs of a new smartphone.

BBRY announced at the Mobile World Congress that it is unleashing KeyOne, an Android device that will be produced by TCL. The phone has a professional look that includes aluminum sides, a black-and-silver finish and the classic QWERTY keyboard — one of the iconic aspects of BlackBerry’s smartphones.

The physical keyboard comes with a few interesting features, such as assigning shortcuts to single keys on the keyboard — say, opening an app. The keyboard’s space bar also features a fingerprint sensor.

The BlackBerry KeyOne has a sleek 4.5-inch display with a 1620 x 1080 resolution, making it among the best screens in the industry. The front camera offers 12 megapixels, while the back camera is 8 megapixels. It comes equipped with Android 7.1, 3 GB of RAM and 32 GB of storage.

BBRY shares are up about 3% year-to-date.