The newly-appointed director of football failed to make a single permanent signing during the recent transfer window, landing only QPR striker Loic Remy on a season-long loan deal.
However Kinnear, who has borne the brunt of fans' frustration at the lack of activity, insists he worked hard on a series of targets, only to see potential deals break down because of inflated fees or the demands of agents.
Writing in his programme notes ahead of Saturday's Barclays Premier League clash with Hull, he said: "It was very frustrating that we did not add at least another signing to the squad in the recent window, but it was not for lack of effort.
"It was not an easy task to improve the quality of the current squad with the financial resources at our disposal, particularly in a window in which the value of players was grossly over-inflated and the demands of agents likewise.
"I worked very hard on several targets and we made a number of bids for players, but for various reasons - some of which were outside the club's control - we were unable to secure our targets.
"We will continue to operate in a financially responsible manner, buying only the right players for the right prices and not paying over the odds or making costly knee-jerk decisions.
"This is the reality of a well-run football club that lives within its means. When the deal is right and the player can add real quality and depth to the squad, we have the ability to spend."