UPDATE 1-XRP cryptocurrency tumbles as Coinbase exchange moves to suspend trading

* XRP down 19% to lowest since July

* Coinbase to suspend trading from Jan. 19

* Connected firm Ripple charged with unregistered securities offering (Adds details, context, updates prices)

LONDON, Dec 29 (Reuters) – Cryptocurrency XRP slumped 19% on Tuesday after Coinbase, a major U.S. virtual coin exchange, said it would suspend trading in the digital currency.

California-based Coinbase said on Monday it would suspend trading in XRP after the U.S. Securities and Exchange Commission (SEC) last week charged an associated blockchain firm, Ripple, with conducting a $1.3 billion unregistered securities offering.

Ripple has rejected the charges, saying XRP is a currency and does not need to be registered as an investment contract.

XRP, the third-biggest cryptocurrency, was last down 18.7% at an intra-day low of $0.20, its lowest since July. It has slumped by over half since the SEC move.

The move by Coinbase comes as it prepares for a stock market listing, with a confidential application to the SEC to go public. It would be the first major U.S. crypto exchange to list on the stock market.

Coinbase, one of the most well-known cryptocurrency platforms, said trading in XRP moved into limit only from Monday, and would be fully suspended on Jan. 19.

Financial regulators around the globe are still grappling with how to regulate bitcoin, XRP and rival cryptocurrencies. Investors are watching for regulatory developments that could determine whether cryptocurrencies leap from a niche to a mainstream asset.

XRP, which often moves in tandem with Bitcoin, had rocketed in November to hit its highest level since 2018 as a rally in cryptocurrencies gathered pace. (Reporting by Tom Wilson; editing by Marc Jones, Larry King)