Citigroup (C) Q1 results are the "best among peers so far" and keep the markets interested through Investor Day, UBS Securities in a note emailed Wednesday.

Noting Citigroup's better-than-expected results, UBS said that the Services segment "continues to wear its crown well," with Treasury & Trade Solutions being the driver. The Markets segment beat consensus, aided by Fixed Income, Currencies & Commodities business coming largely in line and Equities business beating Wall Street estimates by 21%, according to the note.

UBS further said that Citigroup repurchased $6.3 billion of shares versus the Wall Street estimate of $4.4 billion in Q1 and that the company will buy back more this year, versus last year.

UBS maintained its neutral rating on the company with a $132 price target.

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