Is MOEX open on Sunday 31 December 2051?

No

No. MOEX does not trade on Sundays.

No trading

See also MOEX hours today and MOEX holidays 2051

Related markets on 31 Dec 2051

LSE	No trading
Xetra	No trading
Euronext Paris	No trading
SIX	No trading
NYSE	No trading
Nasdaq	No trading
TSX	No trading
B3	No trading
TSE Tokyo	No trading
HKEX	No data