By Jennifer Hill, Personal Finance Correspondent

LONDON (Reuters) - Mention the phrase "wrap platform" and, chances are, you will either conjure up images of rap artist Jay-Z on stage or be met with a blank look, but interest in these new financial management tools is growing.

Some say they are the future: the "Blackberry" of financial services where people can hold their entire portfolio -- their individual savings accounts, direct equity investments, offshore holdings, cash savings and self-invested personal pensions (SIPP) -- within a single product wrapper.

The benefits are plentiful: the ability to see all holdings, including a net total, at a glance; switch in and out of asset classes almost instantaneously; and view the value of holdings as they update in real time.

Others, however, warn that the additional layer of costs often involved make this a viable option only for the most sophisticated investor, and that the technology is not yet developed enough to make the platforms fully effective.

Until recently, wraps were little-known in the UK, even in financial services circles. Only a few years ago, independent financial advisers (IFAs) wanting to offer their clients a wrap proposition had few choices: Transact, Skandia, Selestia and Cofunds. (Skandia merged with Selestia last year after the former's acquisition by Old Mutual.)

Interest in the area grew, though, following a damning report by independent insurance analyst Ned Cazalet into the lack of profitability in the insurance sector.

In the Scottish Life-sponsored report, "Polly Put The Kettle On", Cazalet said re-broking existing business from one provider to another cost the industry around 4 billion pounds per year, as pensions providers saw money walking in one door and out of another, with no good justification, every two or three years.

"It made businesses think about where they sit in the value chain: do they run funds or provide product wrappers, or is there more margin in being the enabling system" Shaun Sandiford, director of key accounts at James Hay, the wrap and SIPP arm of Abbey, told Reuters.