Beneficio vs. ganancia vs. lucro

The words 'beneficio', 'ganancia', and 'lucro' in Spanish all refer to the concept of profit in a financial sense. However, the application and context of these words can vary greatly.

Beneficio

Beneficio generally refers to the positive financial return, advantage or profit obtained from a specific action or situation.
Invertir en acciones puede generar un gran beneficio.
(Investing in shares can generate a great benefit.)
Mi trabajo me proporciona no sólo un salario, sino también el beneficio de la educación continua.
(My job provides me not only with a salary, but also the benefit of continuous education.)

Ganancia

'Ganancia' usually refers to the earnings or gains obtained from a business or commercial activity. It's often used when referring to the difference between sale price and cost of production or acquisition.
La venta de estos productos generó una ganancia significativa para la empresa.
(The sale of these products generated significant gains for the company.)
Espera maximizar sus ganancias invirtiendo en tecnología.
(He hopes to maximize his earnings by investing in technology.)

Lucro

'Lucro' is commonly used in legislation and formal speech. It's often associated with exorbitant profit-making and sometimes carries a negative connotation, implying exploitation or unfair gain.
"Lucro cesante" es un término legal que describe una ganancia que se ha perdido debido a un accidente o incidente.
('Loss of earnings' is a legal term that describes a gain that has been lost due to an accident or incident.)
Las empresas de lucro son las que buscan generar excesivas ganancias sin importar el costo social.
(Profit-making companies are those that seek to generate excessive profits regardless of the social cost.)

Summary

While 'beneficio', 'ganancia', and 'lucro' all refer to profit in some way, they each have their own unique shades of meaning. 'Beneficio' is commonly used to refer to general benefits or advantages due to specific actions or situations, 'ganancia' is typically used in business or commerce contexts referring to earned profits and 'lucro' generally refers implicates high amounts of profits with an exploitative undertone, especially used in law terms or formal speech.