"This is a significant milestone for us, and one that we are pleased to reach in such a short amount of time," said Tim Mahoney, CEO of BIDS Trading in the release. Mahoney attributed the growth in volume to "overwhelming industry support right out of the gate."

In March, six new firms, Bank of America, Bear Stearns, Credit Suisse, Deutsche Bank, JP Morgan and Knight Capital Group joined the original consortium comprised of Citi, Goldman Sachs, Lehman Brothers, Merrill Lynch, Morgan Stanley and UBS, bringing the total number of investors to twelve.

On the other hand, some of the third party ATSs took years to develop significant and sustainable volumes so BIDS still has to catching up to do. On May 1st NYFIX Millennium had a daily record of 82 million shares, and averaged about 51 million shares in April. Liquidnet, the buy-side only block-crossing marketplace, broke a single-day record of 90.8 million shares in late April. For the first half of 2007, Liquidnet is averaging 56 million shares a day, according to a spokesman. (A quarterly announcement will go out next week with more details.)

To solve the solve the paradox of needing to find a trading counterparty without revealing information about the order, BIDS lets the trader control the amount of information that is disclosed about the order using "various customizable tools," according to the release. Traders can choose to auto-execute or negotiate – which is a blend of Pipeline vs. Liquidnet, respectively. Traders can set their minimum block size to protect their order and even filter out counterparties based on past trading behavior. Again this seems to address features found in existing systems. For example, Pipeline builds minimum order sizes based on the stock's market cap and Liquidnet expels members that are suspected of fishing for information. BIDS is open to all sell-side firms and their sponsored buy-side clients as well as algorithms, hedge funds and program traders, countering the exclusivity of Liquidnet’s institutional match which is closed to sell-side firms.

Meanwhile, competition for block trading will be heating up soon as two major exchanges both expand and enter the dark pool arena. Nasdaq is due to launch a continuous block cross later this year, while NYSE Euronext is in the process of testing NYSE MatchPoint, an intra-day crossing network for portfolios or lists of stocks based on a benchmark reference price.