(Sharecast News) - Norway's sovereign wealth fund is understood to be selling down its holdings in smaller UK stocks, it was reported on Monday.

According to Sky News, Norway's Norges Bank Investment Management (NBIM) is selling stakes in "scores" of small and mid-cap companies quoted on the London Stock Exchange. Its positions in larger UK listed companies are not thought to be affected.

Citing City sources, Sky said several unnamed institutional investment groups had seen specific NBIM asset management mandates curtailed in recent weeks.

It is not clear why the $2trn fund, which invests revenues from Norway's vast oil and gas reserves, would be reducing its exposure to smaller London-listed stocks. However, global equity markets have surged over the last year, despite mounting geopolitical risks and subdued economic growth.

In the UK, the FTSE All-Share has put on 19% and the FTSE 250 13%. The blue chip index has risen 20%.

Much of the global growth in equity markets has been driven by tech stocks, on the back of the artificial intelligence boom.

Some market veterans, including JPMorgan Chase's Jamie Dimon, have warned of a potential AI bubble, though so far markets remain bullish.

NBIM said in December when questioned that it had not reduced its exposure to the UK. It has yet to comment on the latest report.