Everton last week sacked manager Rafael Benitez after a 2-1 defeat against relegation-threatened Norwich, a result that left them languishing in 16th place in the table.
"I write to you to assure you that my commitment remains strong and focused," Moshiri said in a letter to fans.
"The club has announced today the conversion of a £100m loan to the club into equity which is a clear demonstration of my commitment and greatly strengthens the balance sheet.
"I am a private man and I do not speak publicly very often. But I promise you that my determination to deliver for Everton will not waver."
Duncan Ferguson will take caretaker charge of the Toffees for Saturday's clash against Aston Villa.
Former England internationals Wayne Rooney and Frank Lampard and Italy's 2006 World Cup winning captain Fabio Cannavaro have been linked with the job on a permanent basis.
Rooney had two spells at Goodison Park as a player and has impressed in difficult circumstances as he tries to keep Derby in the second-tier Championship despite a 21-point deduction due to financial problems.
The Rams are in administration but are just eight points adrift of safety.
"Of course Everton is a club I grew up supporting," Rooney said on Friday.
"I'm flattered to get brought up in those conversations, but I know Everton know that to have any communication with me they have to go through the administrators."