Citigroup's (C 0.89%) first earnings release of 2021 -- published on Friday morning -- was a combination of encouraging and discouraging developments, perhaps leaning a bit more toward the latter.

For its Q4 of fiscal 2020, the bank earned just under $16.5 billion in revenue, which was down from the $18.4 billion in the same quarter the previous year. That was on the back of a 3% year-over-year decline in loans, although the company's total deposits saw significant growth of 20%.

Net income, like revenue, also declined, landing at $4.6 billion ($2.08 per share) versus Q4 2019's $5.0 billion. There's a very large asterisk next to this figure, however; a credit reserve release lifted the metric by $1.5 billion. This in turn boosted the per-share figure to well above the average analyst estimate, which, according to Zacks, was $1.35.

A partially opened bank vault with light emanating from it.

Image source: Getty Images.

On the other hand, those prognosticators were expecting a bit more in revenue; their collective estimate was $16.7 billion.

The top line was affected by reduced take in the Americas and Asia, particularly in the retail banking and credit card segments. However, encouraging gains were recorded within the company's institutional clients group division, with revenue from securities trading and affiliated services enjoying a 13% rise.

In the press release detailing the results, CEO Michael Corbat was quoted as saying that Citigroup remains "very well capitalized" to the point where it will be able to restart share buybacks, as permitted by a policy change enacted in December by the Federal Reserve. Corbat added that the bank intends to resume its share repurchases at some point this quarter.

Likely because of the boost provided by the credit reserve release, investors were underwhelmed by the results. Citigroup stock closed Friday down nearly 7%.