The record now stands at 2009, when LG posted an operating profit of 2.6 trillion won.
Market bellwether Samsung Electronics sank 3.11 percent 2,525,000 won after releasing its fourth-quarter earnings guidance at $14 billion, a record figure but below market expectation.
Preliminary revenue for the December quarter advanced 23.8 percent over the year to 66 trillion won (61.9 billion US dollars).
The results were below analysts' expectations.
Sales are estimated to have increased 14.8 percent over the cited period to 16.9 trillion won, it added.
He said for 2018, LG Electronics is expected to maintain relatively sound returns on the back of the home appliances and TV businesses, although prospects for the handset division remain cloudy.
Tech shares had a bearish day ahead of the earnings season as analysts raised concerns over the impact of a stronger won and lower chip prices on major exporters. The tech giant is expected to elaborate on the results in its finalized report, which will be delivered later this month.More news: Tuesday forecast: cloudy skies, high 55 with chances of wet weather overnight
The ratio of Samsung's operating profit to revenue in 2017 reached a fresh high of 22.4 percent.
Lee Seung-woo, a researcher at Eugene Investment and Securities, expected Samsung to continue with solid earnings in the first-quarter of this year, though the strong Korean won versus the US dollar could be a drag.
The local stock market opened higher taking a cue from overnight USA gains, but the index slipped in afternoon trades to close lower.
The company's operating profit for the entire year could be record-breaking thanks to its chip business.
LG did not offer a net profit estimate for the fourth quarter, nor breakdowns for each segment. Samsung is said to be working on a folding smartphone set ...
This photo taken on January 9, 2018, shows South Korea's largest conglomerate Samsung's offices in Seoul.