GameStop (GME)

Meme stock GameStop rallied as much as 75% at the market open before coming down to 34% on speculation that Keith Gill, the man who inspired 2021′s short squeeze, could currently have a significant position in the video game retailer.

Gill, who goes by "Roaring Kitty" on X and YouTube and "DeepF—Value" on Reddit, appeared to post a screenshot that shows a $181.4m (￡142.6m) position in GameStop stock and options.

The options would allow him to buy the stock at $20 per share.

Read more: FTSE 100 LIVE: Europe in the green as London stocks make biggest jump in a month

“Recent renewed interest in meme stocks, coming as the main US indices struggle to make new highs, is a sign of excessive over exuberance and is more likely a negative portent given the rising headwinds in the markets,” Robert Lea, a Bloomberg Intelligence analyst, said.

GameStop largely relies on brick-and-mortar stores and has been grappling with customers turning online for buying video games and collectibles.

Steve Sosnick, chief strategist at Interactive Brokers, warned investors against chasing the rally.

"Is whoever controlling this account doing this in your best interest, or in their best interest? And, really, you should think that one through because to me it [is] pretty obvious whose interest it's in," Sosnick told Yahoo Finance on Monday.

"If you're chasing the stock up here, you're more likely than not the source of liquidity for whoever is controlling this account to sell into your enthusiasm."

Bitcoin (BTC-USD)

Bitcoin price rose slightly on Monday adding 1.74% on the day to reach $68,858 at the time of writing. However, overall, it has remained tightly rangebound since it failed to top $70,000 again in late May.

Bitcoin saw little price movement even as El Salvador president Nayib Bukele — who had adopted the cryptocurrency as legal tender in 2021 — was re-elected for a second term over the weekend.

Read more: Crypto live prices

The price has also been supported by Donald Trump fans, after the former US president added the option to accept bitcoin as campaign donations.

Despite declining gains, bitcoin investor Peter Brandt is predicting the cryptocurrency could reach $150,000 by September 2025.

Saudi Aramco (2222.SR)

Saudi Aramco’s executives are expected to hold a series of events in the UK and US as they seek to drive up interest for a $12bn share sale.

Saudi Arabia’s state-owned oil giant axed an international roadshow for its $29.4bn initial public offering five years ago after overseas investors casted doubts at its valuation expectations, leaving the government reliant on local buyers.