General Electric Co (GE.N), which was the most valuable publicly traded U.S. industrial conglomerate at the beginning of the year, could sink to the No. 4 spot after a prolonged selloff that has shaken confidence in the company.

Valued at close to US$580 billion at the turn of the millennium, GE has dropped to around US$125 billion and it was surpassed in value by 3M Co (MMM.N) in January for the first time since the 1970s.

At one point last week, the gap between GE and fellow U.S. industrial Honeywell International Inc (HON.N) was US$6 billion, or 5 per cent. The difference between GE and United Tech Corp's (UTX.N) market values fell to US$15 billion.

Helping to narrow the gap is a 45 per cent slide in GE stock over 2017 and a 16 per cent fall this year.

Driven in value by a series of investments in several sectors during the 1990s, GE is now paying the price for focusing outside its traditional industrial manufacturing turf, while its rivals have enjoyed a more steady ascent thanks to a sharper focus on their industrial roots.

"All the large-cap diversified industrials like Honeywell, United Technologies and 3M to name a few, have benefited from some of the money that's come out of GE," said JPMorgan analyst Steve Tusa, who has a five-star rating on Thomson Reuters Eikon for recommendation performance.

"You're really talking about maybe a mid-teens stock at 2020 ... US$20 I think is a very long-term target that really isn't in the equation at this point," Tusa said of GE's shares, which closed at US$14.64 on Monday.

Tusa rates GE's stock "underweight" with a price target of US$14.

But some analysts are optimistic about GE's stock and future prospects.

William Blair & Co analyst Nicholas Heymann believes that the worse could be over for GE, and its shares are likely to begin stabilizing before moving higher as 2018 progresses.

"I think GE shares have been a bit oversold due to excessive fears about liquidity," Heymann wrote in a note.

Heymann cites higher oil prices, improving performance of GE's aviation and healthcare businesses, and the recent nomination of three "exceptionally talented" directors to GE's board. He has an "outperform" rating on the stock.

GE shares slid even after the company replaced Jeff Immelt as CEO last August with John Flannery. His turnaround plan, which includes cutting jobs, slashing GE's dividend and a possible break-up of the conglomerate, is likely to take a year or more to show results.

When Immelt took over in September 2001, GE was the most valuable U.S. publicly traded company. But during his tenure, which ended July 2017, the stock price fell about 40 per cent.

Over Jack Welch's stint as CEO from 1981 to 2001, GE's value rose from US$13 billion to several hundred billions of dollars. Welch has since written or co-written bestselling books on management.