With animal spirits on the rise, companies armed with cheap financing are fueling a new merger wave, but that's not likely to do much to heat up the stock market.

The more than $23 billion buyout of Heinz announced by Berkshire Hathaway and 3G Thursday capped a week of active deal making. There was also the much-anticipated merger of American Airlines and US Airways Thursday, and Comcast's $16.7 billion deal to buy out GE's minority stake in NBC Universal (CNBC's parent). According to S&P Capital IQ, there are $190 billion U.S. announced mergers so far this year, compared to $58 billion at the same time last year.