* Reported Q2 loss unexpectedly
* Interest income significantly lower than expected-broker
* Shares fall by 5 percent
(Adds shares move, analysts comment)
MOSCOW, Sept 24 (Reuters) - Shares in St Petersburg Bank fell after the bank unexpectedly slipped into the red in the second quarter on Thursday.
Shares in the bank lost 5.02 percent at 0750 GMT underperforming the broader market index, which was down by 0.22 percent, and main banking shares Sberbank and VTB
"Significantly lower than expected interest income, which is the main source of income for banks, is particularly negative, while provisions for bad debt are a less reliable indicator," broker Rye, Man & Gor Securities said in a report.
The result could be a bad sign for Russia's hundreds of regional banks, which, unlike industry giants Sberbank and VTB, lack state support and are even more heavily exposed to Russia's first recession in a decade.
Another bellwether for the regional banking industry, Vozrozhdenie, beat second-quarter forecasts, however, when it reported last month.
St Petersburg Bank posted a net loss of 288.9 million roubles ($9.63 million) for the second quarter. A poll of nine analysts had forecast the bank would post a 10 million roubles net profit.
"In the first half of the year the impact of the crisis started to be felt on the balance sheet ... Now our main tasks are to increase the quality of assets and the capital adequacy ratio," Alexander Savelyev, the bank's chief executive officer said in a statement.
In the second quarter of last year, St Petersburg Bank had a net profit of 1.12 billion roubles.
In the first quarter this year profits fell 62 percent to 240.2 million roubles, but the bank said it expected to stay in the black during the course of the year. ($1=30.00 Rouble) (Reporting by Dmitry Sergeyev; Editing by Jon Loades-Carter)