According to an American Banker story last week (here), as of Feb. 1, ING Direct had cross-sold 42,000 (see note 1) checking accounts to its 4.3 million savings customers, a penetration of 1%. Keep in mind, the new checking account has been slowly rolling out over the past 60 days to current customers only (see note 2), and is not yet mentioned on the bank's website. It is expected to be launched to the general public within the next 30 days. 

You can view these initial results in two ways: 

Glass is half full — Even with just 42,000 accounts, ING Direct may have the largest "Internet only" checking account base, at least when measured by the number of active accounts

Glass half empty — Because ING Direct's checking account pays 50 to 80 basis points (0.50% to 0.80%) more than savings on $50,000+ balances, many (most??) of the new checking account customers simply moved large balances into the checking option, providing few incremental deposits.

Notes:

1. Make that 42,001 accounts. I just opened one this morning. It took all of about 30 seconds to do it. Existing customers simply choose an account nickname, enter the dollar amount they want transferred into the account (from the pre-existing link from an outside account), and agree to the disclosures. See below for the confirmation screen.
2. I received my invitation to open an Electronic Orange account last week (screenshot here). I've had an account there since 2001.

For the first time in its short six-year history, ING Direct's U.S. division showed declines in both total deposits and customer accounts during third quarter, the latest data available (see the table below, originally published in our year-end industry forecast, Online Banking Report #137). Although the runoff was relatively small – $600 million in deposits, or about 1% from the peak, and 150,000 accounts, or about 4% from the peak – it's a clear indicator that the entry of Emigrant Direct, HSBC Direct, and especially Citi Direct have taken a toll on the direct banking giant.

Looking at quarterly results below, you can see that average account balances began declining in Q1 2005, as some of the hottest money, large balances held by extremely rate-conscious consumers, moved to better paying accounts; still, total deposits and customers continued to grow rapidly through 2005 and into 2006. However, in the second and third quarters, deposits began to flatten as the number of accounts grew only 230,000 compared to 560,000 in the same period a year earlier.

ING Direct appears to have deliberately slowed growth by maintaining deposit rates 50 to 100 basis points lower than the new entrants. With its marketing muscle, the bank could choose to grow deposits if it closes the rate gap. The bank's new checking account, gradually rolling out to current customers, may help stem the tide, with higher rates for larger balances (see coverage here).

Table: ING Direct Deposit and Customer Totals: 2000 to 2006 (click to enlarge)

PDF version of this table here.