Four Israeli hi-tech firms made it to tech mag Upside's list of the 100 hottest companies.

XaCCT, Chiaro Networks, BigBand Networks and Mellanox Technologies made the grade of companies boasting a killer combo of promising technology, business model, and significant growth over 12 months.

XaCCT was established in 1997. The company is developing technology to enable Internet access and telephony providers to accurately track data transmission over different types of networks, and to monitor the use surfers make of added-value services.

Since its establishment, XaCCT has raised $52 million in five financing rounds. A year ago it stepped back from a public issue according to a company value of $270 million. Shareholders include Sun Microsystems (Nasdaq:SUNW), Ampal-American Israel Corporation (Nasdaq:AMPL), and several venture capital funds.

Its client list includes Britain's Cable & Wireless (LSE:CW), Siemens, UUNET and Worldcom (Nasdaq:WCOM). Six months ago XaCCT announced a $35 million deal with Motorola (NYSE:MOT) and Bell Canada.

Mellanox, founded in 1999, is working on InfiniBand chip architecture. In February it raised $56 million at an estimated post-money company value of $250 million. Its stellar group of investors included Banc of America Securities, Dell Computer Corporation (Nasdaq:DELL), Sun Microsystems, JNI and Quanta Computers.

Mellanox's 2001 revenues are estimated to have been $5 million.

BigBand Networks, established in 1999, supplies broadband infrastructure systems for television and advanced broadcast services. A month ago the company finished raising $27 million at a post-money company value of $60 million. Its clientele includes Time Warner (NYSE:TWX), Rogers Communications (NYSE:RG), Blue Ridge Communications and Cox Communications (NYSE:COX).

Dolev & Abramovitch Hi-tech Information estimated BigBand made $6 million to $7 million last year.

Chiaro Networks, founded in 1997, develops optic and electronic communications systems for speeds of 10 gigabit per second. Its target is the world's biggest communications companies.

Last February Chiaro raised $80 million in its fourth round, at a post-money company value of $205 million. No income reported so far, though.