Set amid woodland with a picturesque lake, the resort is co-owned by the family of Yuri Kovalchuk, another old friend of Putin, and a Cyprus company with undisclosed shareholders.
One person who attended the event said staff were told the bride and groom were named Kirill and Katerina, and that guests wore white scarves embroidered with the letters "K&K" in red thread. When shown a photograph of a woman known as Katerina Tikhonova, the source identified her as the bride. Tikhonova is Putin's younger daughter, as Reuters confirmed in November.
"Guards were behind every corner, (they) didn't let anyone close to the celebration," said a staff member at the resort, which has a luxurious spa complex. "But we knew it was Kirill and Katerina - Putin's daughter - celebrating marriage."
At the time of the wedding, Kirill - a tall, dark-haired man with rimless glasses - was a rising star of Russian business, but still only 31. His fortunes began to skyrocket soon after his wedding to the president's daughter, a competitive acrobatic dancer who is now helping to oversee a $1.7 billion expansion of Moscow State University.
Within 18 months, Kirill acquired a large chunk of shares in a major Russian oil and petrochemical processor called Sibur - a stake now worth an estimated $2.85 billion, based on the value of recent share deals. He also quit his job as a business manager and set up a company to run his personal investments.
How did such a young businessman go so far, so fast? A Reuters examination of Shamalov's career shows that in the summer of 2013, months after he married Putin's daughter, Kirill opened discussions about buying shares in Sibur from one of the president's wealthiest friends.
A year later, he was able to borrow more than $1 billion, judging by the published accounts of his investment company. The loan came from a bank headed by another longtime associate of Putin, and where Shamalov's brother holds a senior position. The money was used to make an investment in Sibur that within months proved highly profitable for Kirill.
Asked about his business deals and the wedding, Kirill Shamalov and Sibur declined to comment.
The trajectory of Kirill's fortunes sheds new light on how people close to Putin have taken commanding positions in key companies - and how such opportunities are now being extended to a new generation. Like the wedding, much of this transfer of riches has occurred away from public scrutiny.
Vladimir Milov, a former Russian deputy energy minister and now an opposition campaigner, said Putin's friends had acquired major assets with the help of lenders with links to the state, such as Gazprombank.
"It's extremely non-transparent, so it is hard to get to and judge the specifics of the loan agreements," Milov said. "They consider Gazprombank their pocket bank."
He added: "They are looking to pass on their power and privileges to a new generation."
Asked about the wedding celebrations and business deals, Dmitry Peskov, spokesman for the Russian president, said: "Putin's daughters are not involved in politics or business. The businessman, Shamalov, is well known. As far as we are aware, all his activities are in line with the laws of the Russian Federation. For many years he has been in the management of the company Sibur, and along with other senior managers is a shareholder. His career and business are not within the sphere of interest of the Kremlin. We do not give comments on the private lives of Putin's close relatives."