* This content was produced in Russia where the law restricts coverage of Russian military operations in Ukraine (Adds analyst comment, updates prices)
MOSCOW, June 30 (Reuters) - The Russian rouble rallied on Thursday, heading towards its strongest levels since 2015 as it retained support from high commodity prices, while shares in Gazprom plummeted after the gas giant said it would not pay dividends.
Gazprom shares fell 29% to 211 roubles ($3.91) by 1411 GMT after the company said its shareholders had decided against distributing dividends on the 2021 results.
The decision put some pressure on the rouble as investors usually convert dividend payments they receive into foreign currency and other assets.
"The absence of dividends will negatively affect the sentiment of the stock market participants. The paper formed a third of the portfolios of Russian private investors," VTB Capital analysts said.
The lack of Gazprom payout this year removed additional short-lived support for the rouble, said Dmitry Polevoy, head of investment at Locko Invest.
But the rouble firmed on the Moscow exchange, adding more than 3.5% on the day to 51.25 against the dollar and heading towards the 50 mark that it hit on Wednesday for the first time since May 2015.
Against the euro, the rouble rose 4.3% to 53.55 , having climbed beyond 53 earlier this week for the first time since April 2015.
The rouble has become the world's best-performing currency this year, boosted by measures taken to shield Russia's financial system from Western sanctions imposed after Moscow sent troops into Ukraine on Feb. 24.
The measures have included restrictions on Russian households withdrawing foreign currency savings.
The strong rouble has raised concerns among officials and export-focused companies, because it dents Russia's income from selling commodities and other goods abroad for dollars and euros.
On Wednesday, Finance Minister Anton Siluanov said Russia could cut state spending and channel funds for foreign currency interventions to keep a lid on the rouble's strengthening, which threatens budget revenue.
The central bank could also ease upside pressure on the rouble by cutting interest rates as inflation slows and the economy needs cheaper credit. The central bank is expected to cut the key rate to 9% from 9.5% at its next board meeting July 22, a Reuters poll showed on Thursday.
Russian stock indexes were down. The dollar-denominated RTS index fell 3.7% to 1,360.5 points, dragged lower by Gazprom. The rouble-based MOEX Russian index was 6.7% lower at 2,218.3 points. ($1 = 53.9990 roubles) (Reporting by Reuters; Editing by Tomasz Janowski and Alison Williams)