There's a good reason Carlos Slim is ranked the 17th richest person in the world by Forbes: He knows a good bet when he sees one.

And a recent gamble -- pumping money into WorldCom after it went bust amid a welter of fraud allegations -- looks to have paid off handsomely.

If past Wall Street estimates are accurate, his investments in WorldCom bonds look to have netted Slim about $600 million following today's news that Verizon Communications Inc. (NYSE: VZ) is to buy MCI Inc. (Nasdaq: MCIP) (see Verizon Wins Tussle for MCI).

The Mexican businessman -- full name Carlos Slim Helu -- is believed to have invested about $300 million in WorldCom bonds after the carrier went into bankruptcy protection, as he picked up the assets at anything between 10 cents and 20 cents on the dollar (see Sun Drives Linux ).

The $300 million estimate, first published in The Wall Street Journal, was made by investment sources in April 2004, just before WorldCom emerged from Chapter 11 under its new name of MCI (see MCI Starts a New Chapter).

Those bonds were converted into 42.6 million shares when MCI listed on the Nasdaq exchange, giving Slim and his family 13.4 percent of the common stock.

Fast forward to today: If the terms and conditions of the Verizon acquisition remain the same, Slim's MCI stake will be worth $883.95 million, about $584 million more than he invested in the bonds, and a near 300 percent return on the original investment.

Slim, estimated by Forbes to be worth $13.9 billion, couldn't be contacted for comment on this matter. [Ed. note: Amarillo Slim was likewise unavailable.]

Given Slim's apparent success with his MCI investment, attention might now turn to his interest in another formerly bankrupt carrier, Global Crossing Holdings Ltd. (Nasdaq: GLBC), in which his investment vehicles hold a 19.9 percent stake.

That stake gained more than 2 percent in value today as Global Crossing's share price jumped 35 cents to $16.95. That price values the carrier at $373 million, and Slim's stake at a seemingly modest $74 million.

That's in contrast to MCI's share price, which dipped 96 cents, nearly 5 percent, to $19.79, after investors realized the Verizon deal didn't offer a premium to Friday's closing price, and that the deal will take about a year to close.

Verizon's share price rose 47 cents, about 1.3 percent, to $36.78, while Qwest Communications International Inc. (NYSE: Q), the RBOC that lost the MCI bidding war, saw its stock drop 27 cents, about 6.5 percent, to $3.88.

— Ray Le Maistre, International News Editor, Light Reading