LONDON (Reuters) - Thyssenkrupp shares leapt 20 percent on Friday as investors rushed to cover bearish bets after the conglomerate announced plans to list its best business, a move long hoped-for by investors.

FILE PHOTO: A logo of Thyssenkrupp AG is pictured at the company's headquarters in Essen, Germany, November 21, 2018. REUTERS/Thilo Schmuelgen

The stock was up 21% at 13.62 euros ($15.31) at 1407 GMT, set for its best day since the German firm’s listing in 1991. They were the best-performing shares in Europe.

Thyssenkrupp is considering a carve-out or listing of its elevators business after abandoning plans to split itself up with a cross-shareholding structure and pulling the plug on a joint venture with Tata Steel.

The shares rose as investors scrambled to cover large bearish bets, analysts and traders said.

On Thursday, the level of short interest was 38.3 million shares, the largest amount in more than four years, according to data from FIS Astec Analytics. Around 6.1& of Thyssenkrupp’s outstanding shares wee out on loan.

On the day the joint venture with Tata Steel was announced in Sept 2017, Thyssenkrupp shares were trading at 26.2 euros - nearly twice their current level.

That means even after today’s jump, short sellers would still have made a 50 percent gain on their investment, if they went short on that day.

Conglomerates, viewed by some investors as inefficient and hard to value, are often saddled with a discounted valuation by investors. Specialized businesses can attract higher values when they do not have to compete on a combined balance sheet with other group businesses offering lower returns.

In similar moves to Thyssenkrupp, General Electric spun off its healthcare business and Siemens plans to separate its gas turbines business.

If Thyssenkrupp lists its elevators business at similar valuations to those Kone and Schindler trade on currently, it could deliver an enterprise value of 14 billion euros, Jefferies analyst Alan Spence said.

“There’s significant value within the elevators business which the conglomerate discount placed on Thyssenkrupp has historically masked,” he wrote.

The sharp share price reaction on Friday, such as the one seen recently when a new investor joined SAP, may also suggest investors are giving Europe Inc renewed attention after years of worries about slowing economic and earnings growth.