(Updated to add reference to competing double-exposure ETF in fifth paragraph.)

Credit Suisse, the sponsor behind the VelocityShares Daily 2X VIX Short-Term ETN (NYSEArca: TVIX), temporarily suspended creations of shares of the exchange-traded note because assets in the security had grown beyond what the bank, in a press release, called “internal limits.”

While Credit Suisse officials weren’t immediately available to elaborate on the press release, it appears that the halting of TVIX creations has nothing to do with any sort of limit imposed by regulators.

What is clear is that the ETN’s assets have been expanding rapidly in recent weeks. TVIX had $691.8 million in assets as of Feb. 21, according to data compiled by IndexUniverse. The ETN had just under $500 million in assets only two weeks ago.

“This suspension does not affect the early redemption rights of noteholders as described in the pricing supplement,” Credit Suisse said in the press release. It stressed that other ETNs it issues aren’t affected by the halting of TVIX suspension.

Volatility products related to VIX futures have grown in popularity since the market meltdown of 2008-2009. They are regarded as portfolio insurance because they spike in value when stocks are in full retreat. A double-exposure product that competes with TVIX, but in an ETF wrapper, is the ProShares Ultra VIX Short-Term Futures ETF (NYSEArca: UVXY). It now has about $27 million in assets.

One of the oldest and most successful VIX-related ETN is the iPath S&P 500 VIX Short-Term Futures ETN (NYSEArca: VXX). It had just over $1 billion in assets as of the Feb. 21 close.

While VelocityShares markets the ETNs that bear its name, Credit Suisse issues them. That means that any ETNs it issues, including TVIX, are based on the full faith and credit of Credit Suisse.

Many sources in the exchange-traded product industry say the credit risks associated with any ETN may be slowing down growth in the segment.

VelocityShares, which rolled out its first strategies last year, was co-founded by Greg King, Richard Hoge and Nick Cherney in 2009. Cherney is also the company's chief investment officer.

King left VelocityShares and is now at Credit Suisse.

VelocityShares has 22 ETNs with $1.2 billion in assets.