The phrase "a favourable gain" is correct and usable in written English.
It can be used in contexts where you want to describe a positive or advantageous increase, often in financial or business discussions.
Example: "The company reported a favourable gain in profits this quarter, exceeding all expectations."
Alternatives: "a positive gain" or "an advantageous increase".
United head into Tuesday's Champions League encounter with Shakhtar Donetsk at Old Trafford still requiring a point to ensure top spot in Group A to gain a favourable knock-out round draw.
Károlyi hoped to gain a favourable peace settlement from the Allies but was disappointed.
Great drama rests on an unresolvable moral dilemma: will Agamemnon sacrifice his daughter to gain a favourable wind?
Manchester United became the first sports team in the world to be valued at $3 billion SHAKHTAR DONETSK Shakhtar will be extremely pleased with their coefficient score this season which could see them gain a favourable draw in this year's group stage.
The overwhelming Allied victory ensured the safety of Vienna from the Franco-Bavarian army, thus preventing the collapse of the Grand Alliance. Louis XIV of France sought to knock Emperor Leopold out of the war by seizing Vienna, the Habsburg capital, and gain a favourable peace settlement.
A number of studies proved that patients with late-stage NSCLC who received tumour vaccine therapy combined with chemotherapy could gain a favourable prognosis compared with chemotherapy treatment alone.
Seven of Benteke's goals directly contributed to Liverpool gaining a favourable result.
The design of the new study plans adapted to the guidelines of the European Higher Education Area (EHEA) attempt to bring business reality closer to the students, involving them into their learning process adopting an active model and participation and providing them a favourable framework in order to gain different skills.
This locates the strictly aerobic bacterium in a favourable position where it can gain access to oxygen and other nutrients from the nearby photosynthetic micro-organisms without expending energy.
In addition, it is associated with a favourable metabolic profile and minimal weight gain potential.
