INTEL bought MBLY for 15.3 Billion in 2017. 7 years later it has a marketcap of 11.5 Billion USD, 25% lower than what INTC paid for it.

Sources:

Deals and IPOs

Intel to buy driverless technology firm Mobileye for $15.3 billion

Published Mon, Mar 13 20177:49 AM EDT

https://www.cnbc.com/2017/03/13/intel-to-buy-mobileye-for-14-billion-to-15-billion-israeli-media-report.html

IPO

Started with 17B valuation: https://www.cnbc.com/2022/10/26/mobileye-pops-more-than-30percent-in-ipo-after-spinning-out-of-intel.html

Some have speculated that MBLY listing was for the benefit of employees to sell their stock awards if they need cash. Others suggested it was a way for INTC to fund new FAB expansions.

MBLY is not INTC though, it is a seperate company, although it seems some people think they are 1 and the same and if INTC isnt doing well ,the same would go for MBLY.

Edit: It appears INTC sold 38.5 million additional shares for $40.84 per share in June 2023, so Grandma is down 65% if she bought some shares at that time, current buyers can get 3 shares for the price of 1 at that time: https://www.nasdaq.com/market-activity/stocks/mbly/insider-activity