By Tom Wilson and Tom Westbrook

LONDON/SINGAPORE (Reuters) -Bitcoin rose 6% on Tuesday to to $35,198, its highest in nearly a year-and-a-half, on mounting speculation that an exchange-traded bitcoin fund is imminent.

That followed a 10% surge on Monday, when bitcoin posted its best day in almost a year, and the bullishness spread across the wider crypto market and into related stocks.

Any approval by the U.S. Securities and Exchange Commission (SEC) of an exchange-traded fund (ETF) that owns bitcoin on behalf of fund investors is predicted to fuel demand.

A spot bitcoin ETF, the argument goes, would allow investors previously wary of crypto access to the asset via the stock market, ushering in a new wave of capital to the sector.

"The value of ... any asset, basically, is the amount of people using it," said Steen Jakobsen, CIO at Saxo. "So the ETF would make a large audience and increase liquidity."

, a volatile asset whose price has doubled so far this year, was last up 3.2% at $34,129. The second-largest cryptocurrency ether climbed to its highest since August.

Crypto-linked shares such as major U.S. exchange Coinbase (NASDAQ:) Global and bitcoin owner MicroStrategy rose in after-hours trade.

Investment giant BlackRock (NYSE:) is among several major U.S. financial firms with pending applications for bitcoin ETFs.

Speculation on their likely approval was fuelled by BlackRock's iShares ETF listing on the website of clearing house DTCC. It was unclear when or why the iShares ETF was added to the DTCC list. DTCC and BlackRock did not immediately respond to requests for comment.

Anticipation also grew after reports this month, including from Reuters, that the SEC won't appeal a court ruling it had been wrong to reject an ETF application from crypto firm Grayscale Investments.

"The SEC being pressured by the courts increases the probability" of an ETF approval, said Standard Chartered (OTC:)'s head of digital assets research Geoffrey Kendrick.

Last week BlackRock denied an erroneous report that its ETF had been approved.

Data on crypto derivatives analysis site Coinglass showed heavy bitcoin short-covering in the last 24 hours.