Mr Lightbody was hailed by the judging panel at the event, which is backed by accountancy firm Grant Thornton, for his role in tackling Finsbury's debt pile and a "transformation" in its share price.
They also highlighted his "pivotal role" in the £21 million deal to offload the United Central Bakeries division, based in Bathgate, West Lothian, to gluten free specialist Genius Foods.
Meanwhile, Mr Nimmo was congratulated for returning £7000 on every £1000 invested in the Standard Life UK Smaller Companies Trust in the past 10 years.
Philip Secrett, head of public company advisory at Grant Thornton, said: "His consistent process and concentrated portfolio has delivered truly extraordinary results that are in excess of even the excellent performance of his peers."
Ithaca Energy, which has its UK base in Aberdeen, won the deal of the year category for its £203m swoop on fellow North Sea focused oil company.
The Judges said: "The deal saw Ithaca considerably expand its scope and assets after swallowing its rival."
The awards were held at the Natural History Museum in London.