NEW YORK (CNN/Money) - Procter & Gamble and Gillette. SBC and AT&T.

If you're dizzy from the big-name mergers and acquisitions already announced this year, experts say you ain't seen nothing yet.

Monday brought news of two 11-figure deals -- SBC (Research) announcing the $16 billion acquisition of former parent AT&T (Research), and MetLife (Research) agreeing to buy the Travelers Life & Annuity unit of Citigroup (Research) for $11.5 billion.

But both transactions pale compared to the $57 billion deal announced Friday for P&G (Research) to buy Gillette (Research), the biggest merger in P&G's history.

Strong corporate balance sheets, the prospects for earnings growth and still relatively low interest rates needed for affordable financing could result in only the fourth trillion-dollar M&A year in U.S. history. It would be the first trillion-dollar year since the white-hot late-90s bull market ended with a record $1.7 trillion in deals announced in 2000.

"This is the opposite of the perfect storm, the perfect calm that makes this a good time for M&A activity," said Richard Peterson, market strategist for Thomson Financial, which puts the value of deals announced in January at $123 billion. That's up about 50 percent from the January 2004 total.

Steven Bernard, director of M&A Market Analysis for Robert W. Baird & Co., said the prime factor in the increased deal making is the improving economy, which has had the effect of lifting companies' stock prices and cash reserves needed for deals.

"Internal growth is getting more and more difficult. After two years of companies looking internally, they're using the stock prices to look at acquisitions," Bernard said.

Bernard said the sellers are now accepting offers because of strong pricing available, rather than the distressed sales often seen from 2001 through early 2003.

"In the last couple of years, if you had a good business but it wasn't a core business, you hung onto it waiting for the market to turn," he said. "Now there's an opportunity to sell at an attractive price."

Monday's MetLife-Travelers deal undoes part of the Travelers-Citibank deal that combined the insurance and banking giants in 1998. That kind of unwinding of past deals could spur some of the increased M&A activity going forward, Bernard said.

"It can be unwinding some of the bad deals that were done, or increased pressure from investors and board to focus on core business," said Bernard.

While January was the best first month of the year since 2000, when the America Online-Time Warner deal (of which what is now CNN/Money was a part) was announced, it actually is a bit behind December's total, when almost $200 billion in deals were announced. That means the last 60 days has seen greater deal volume than posted in any year from 1989 through 1993.

"Those of us who track this are playing catch-up with the deals, trying to get the all the volume totals," said Peterson.

Peterson and other experts said that some of the deals announced already could spur competitors to announce their own moves in response, adding fuel to the M&A surge.

"SBC may lead other regional carriers to look at other acquisitions," said Peterson, citing talk of buyers now looking more closely at AT&T competitor MCI (Research). "On heals of the Sprint (Research)-Nextel (Research), we saw Western Wireless (Research) be acquired by Alltel (Research).

Greg Gorbatenko, analyst for Marquis Investment Research and a critic of the SBC deal for AT&T, said he believes problems with the deal will stop competitors from following.

"I don't know why you want more of a evaporating business that will slow your revenue growth and lower your margins," said Gorbatenko.

But Gorbatenko agreed that the market for tech deals in general is strong, as some companies seek to make acquisitions before bargains and opportunities disappear.

"The market has been sucking air for so long, these valuations are still pretty low," he said. "It's safe to say there will be more deals, more consolidation. I've had three big companies I cover disappear just in the last couple of months."