Russian oil major Rosneft is one of the main investors in Credit Bank of Moscow (CBOM), according to a report by Russian daily Vedomosti.

Recently, CBOM completed a successful SPO and unconfirmed reports suggested that the bank was pressured to reinforce its capital by worried investors that bought into its subordinated instruments.

CBOM had to boost the capital adequacy ratio after it was included in the systemic bank list in September 2017. Analysts surveyed by Reuters estimated that the bank's capital would increase by about 9% after the SPO making it safely comply with the requirements.

However, the bank recently said that it had increased its capital by RUB22bn by raising corporate subordinated deposits. Allegedly, a number of subsidiaries of Russia's largest oil producer – Kremlin-controlled Rosneft – provided CBOM with these RUB22bn worth of 49-year subordinated deposits at 8.75% interest. In 2015 Rosneft also provided CBOM with a subordinated loan worth $300mn maturing in 2021 with a prolongation option until 2025.

Unnamed market participants surveyed by Vedomosti closely relate Rosneft to CBOM, claiming that Rosneft is one of the main depositors of the bank, although not participating directly in the share capital.

It is also claimed that shortly prior to the controversial bail out of Financial Corporation Otkritie, Rosneft moved its funds from the bailed bank to CBOM. Fitch Ratings suggested that CBOM received RUB208bn worth of repo deals out of RUB372bn of such deals that were halted at Otkritie.

Should CBOM join Otkritie and B&N Bank and become one of the major systemic banks to be bailed out by the Central Bank of Russia, Rosneft would lose all of the subordinated funds in the bank.

Last month the perpetual bonds of CBOM tanked as fears that another so-called Garden Ring bank could go to the wall continue to dog the market.

However, on the same week Moody's Investors Service upgraded the long-term local- and foreign-currency senior unsecured debt and deposit ratings of CBOM to Ba3 from B1, while changing the outlook to Stable from Positive.

Moody's believed that the upgrade of CBOM's ratings reflected the high probability of the bank's senior debt and deposits benefiting from support from the central bank.