NEW YORK ( TheStreet) -- Given his extensive interviews and widely read op-ed pieces, it's clear that Warren Buffett is never against sharing his opinion with the public. In many cases, however, he appears willing to let his wallet do the talking.This week in a letter to Rep. Tim Huelskamp (R., Kan.), billionaire investor Warren Buffett stated that he had made nearly $63 million last year. What's more, the Nebraska native, who has recently come out as a vocal proponent of tax increases for the super wealthy, also remarked that his federal taxes totaled less than $7 million, or 17.4%. These tax figures were reflective of those Buffett had mentioned in his most recent New York Times op-ed piece, "Stop Coddling the Super-Rich." While this news was enough to steal headlines, it has immediately generated criticism due largely to the fact that Buffett has yet to publicly release his official tax return. This hesitation, however, does not appear to be a sign of unwillingness. On the contrary, in a letter sent to the congressman, the Oracle of Omaha explained that he would be willing to make this information public. However, he is waiting until he can find fellow members of the ultra-wealthy who would be willing to do the same. Buffett feels that this would be useful for the ongoing debate over tax reform. >>View Warren Buffett's Portfolio Following up this stipulation, Buffett offered a challenge to Huelskamp. If he is able to successfully convince another wealthy individual to release his or her tax returns at the same time as him Buffett would, "be willing to have a pre-release wager with anyone who wishes for any sum that they wish," that his figures are exactly those stated in his op-ed piece. It will be interesting to see if this challenge goes anywhere. This tax-related wager is not the first time that Buffett has used a bet to make a point. Long an opponent of the fees charged by hedge funds, in 2008, the Berkshire Hathaway ( BRK.A) chairman threw his hat into the ring against New York-based asset manager Protégé Partners on a bet that, over a 10-year span, a low-cost index fund linked to the S&P 500 could beat out the average returns from five hedge funds chosen by the company.