Mr Royde, previously head of technology stocks at broker Peel Hunt before founding Kestrel, has established the London-based fund manager as the biggest investor in Cupid behind its co-founder Bill Dobbie.
Cupid, which owns sites including Cupid.com, UniformDating.com, and over-45s service Lovebeginsat.com, told the stock market that Kestrel had upped its stake to 14.49%.
Its 10.3m shares are worth around £4.6 million.
Kestrel has boosted its holding by three million shares in recent days according to two filings to the stock exchange.
Mr Dobbie, who stepped down as chief executive five months ago, is the company's biggest investor with 20.61% of Cupid.
Kestrel declined to discuss its investment.
Mr Royde said: "We do not really speak to anyone outside our organisation as to what we are doing and why."
Guernsey-based Kesterel Opportunities fund was established to take advantage of "acute lack of investment in quoted smaller companies".
Cupid's shares, which peaked at 249p three years ago, have been trading below their 2010 list price of 60p in recent weeks. They closed yesterday at 44.25p, up 0.25p or 0.57% on the day.