* PKN Orlen <PKNA.WA> Q3 net profit PLN 21 mln
* Lotos <LTOS.WA> net loss at PLN 238 mln
* Both co's earnings weaker than expected
* Refiners blame zloty, inventory revaluations
* PKN stock down 11.5 pct, Lotos down 8.6 pct
(Adds management comments, updates price)
By Patryk Wasilewski and Pawel Bernat
WARSAW, Nov 13 (Reuters) - Polish refiners PKN Orlen <PKNA.WA> and Lotos <LTOS.WA> posted weaker-than-expected third-quarter earnings on Thursday on the back of inventory revaluation losses and currency operations.
PKN's net profit fell 96 percent year-on-year to 21 million zlotys ($7 million), while Lotos plunged to a 238 million zloty net loss from a 230 million net profit year earlier.
The results knocked PKN shares down 11.5 percent to 26.30 zlotys, while Lotos fell 8.6 percent to 16.15 zlotys. Warsaw's WIG20 main stock index lost 4.3 percent.
Both companies expect adverse conditions to continue in the fourth quarter, with most likely further writedowns on inventory valuations and losses on financial operations.
"Should the current situation on the financial market continue, it cannot be ruled out we will also have a loss on financial operations in the fourth quarter," said Lotos CFO Mariusz Machajewski.
Lotos said in its filing that it had 319 million zlotys in losses on financial operations in the quarter, mainly on hedging operations on the zloty and refining margins.
PKN Orlen's CFO Slawomir Jedrzejczyk also warned the company might be further hit by inventory revaluations in the fourth quarter after suffering a 316 million zloty one-off in the third.
PKN, the country's largest refiner, also declared it would seek buyers for its chemical arm Anwil next year, if it gets the necessary permission from the supervisory board.
"If the supervisory board approves the strategy then we would want to sell Anwil by end 2009," Orlen Chief executive Jacek Krawiec told reporters on Thursday.
The supervisory board is dominated by representatives of the state, the company's largest stakeholder, who appointed Krawiec to take the helm of PKN Orlen.
The third-quarter results were weaker than expected. Analysts had on average put PKN's profit at 71 million zlotys, while forecasting a net loss of 35 million for Lotos.
"Both results are pretty weak," said ING analyst Tamas Pletser. "PKN, at least, met expectations on the operating side, but it was probably a bigger shock to see such a small profit, especially in the environment when refining margins are rising."
In the first half, both PKN Orlen and Lotos benefited from inventory gains as crude prices rose, but now both are suffering as the trend reverses.
Oil prices <CLc1> fell in the third quarter from more than $127 per barrel to just under $100, having hit an all-time record of $147/bbl. They are now just over $55/bbl.
PKN's Czech unit Unipetrol <
> also disappointed investors with a net profit of 552 million crowns ($100 million), below the 576 million expected by analysts.It had a loss of 1.27 billion in the year-earlier period, due to protracted shutdowns as margins in the quarter were hurt by high oil prices. Unipetrol shares fell 4 percent to 119 crowns. (Additional reporting by Piotr Skolimowski, editing by Will Waterman)