On Wednesday (November 23) the firm said it could need another 25 billion euros - close to $26 billion.
That would take the total cost to around $53 billion.
Uniper is the largest corporate casualty of Europe's energy crisis.
It nearly collapsed after Russia's Gazprom - its biggest supplier - cut off gas flows.
That led to the firm posting a record net loss for Germany, and forced Berlin to nationalise it.
The firm then saw hope in a promised gas levy, meant to help importers bear the additional costs.
However, Berlin later scrapped the levy plan, leaving Uniper again needing more aid.
Investors are due to vote on the whole bailout package on December 19.
It will also need approval from competition watchdogs in Brussels.
Uniper says it is in talks with the European Commission, and expects a green light before the shareholders' vote.
Shares in the firm, which were already down over 80% this year, lost around 4% on Wednesday.
