* 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 pct, Lotos down 5 pct
(Adds analyst, share prices, Unipetrol results)
By Patryk Wasilewski
WARSAW, Nov 13 (Reuters) - PKN Orlen <PKNA.WA> and Lotos <LTOS.WA> posted weaker-than-expected third-quarter earnings on the back of inventory revaluation losses and currency operations, which weighed on the Polish refiners' shares on Thursday.
PKN's net profit fell 96 percent year-on-year to 21 million zlotys ($7 million), below the 35 million seen in a Reuters poll. Lotos plunged to a 238 million zloty net loss versus a 230 million net profit year earlier and a 35 million loss seen by analysts.
"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."
By 1006 GMT, PKN shares shed 11 percent to 26.44 zlotys, while Lotos fell 5 percent to 16.63 zlotys. Warsaw's WIG20 index lost 4.2 percent.
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 said the zloty strengthening in the July-September period had cost it 570 million zlotys on the operating level, while inventory revaluations took off another 316 million.
In the first half, both PKN Orlen and Lotos benefitted from inventory gains as crude prices rose, but now both are suffering as the trend reverses.
Oil <CLc1> declined in the third quarter from more than $127 per barrel to just under $100, although its volatile price managed to hit an all-time record of $147 before retreating.
PKN's Czech unit Unipetrol <
> also disappointed investors with a net profit of 552 million crowns ($99.91 million), below the 576 million expected by analysts.It had a loss of 1.27 billion in the year-ago period, when it dealt with protracted shutdowns as margins in the quarter were hurt by high oil prices. Unipetrol shares fell 4 percent to 119 crowns.
Both PKN and Lotos saw revenue improve year-on-year, and beat expectations, thanks to higher refining capacities, sales, and higher average product price.
PKN's revenues rose 34 percent to 22.1 billion zlotys ($7.45 billion), above the 21.5 billion seen in Reuters poll, while Lotos' top line improved 35 percent to 4.7 billion zlotys ($1.58 billion), above 4.3 billion seen in the poll. (Additional reporting by Piotr Skolimowski; editing by Simon Jessop)