...Thursday.
The site quoted an unnamed source as saying ENI bought the stake from ConocoPhillips , doubling its interest in the refiner, 51 percent-owned by Czech oil group Unipetrol .
Unipetrol shares jumped as much as 6.8 percent on Thursday on rumours ENI took the stake at a high price that would also raise the valuation of Unipetrol's stake in Rafinerska.
Unipetrol, a unit of Poland's PKN Orlen , has itself long been interested in raising its stake by acquiring the shares offered by ConocoPhillips.
Traders said the stock was also boosted by a target price hike to 315 crowns from 250 by brokerage Wood and Company.
Italian newspaper Il Sole 24 Ore first reported last week that ENI may have raised its Rafinerska stake, but none of the parties involved have confirmed nor denied the deal since.
ENI, Unipetrol and Rafinerska had no comment on the rumours of the sale on Thursday, and a ConocoPhillips spokesman in the Czech Republic could not be reached.
Royal Dutch Shell holds the remaining 16.3 percent stake in Rafinerska, the biggest Czech crude oil processor.
[PRAGUE/Reuters/Finance.cz]