* Futures up: Dow 0.66%, S&P 500 0.68%, Nasdaq 0.86%

* Trump declares Iran ceasefire extension

* GE Vernova ( GEV ), Boeing ( BA ) rise after results

(Updates before market open)

By Avinash P and Niket Nishant

April 22 (Reuters) - Wall Street's main indexes were on

course to open higher on Wednesday after U.S. President Donald

Trump extended the ceasefire with Iran, even as uncertainty

remained over whether Iran and U.S. ally Israel would honor the

truce.

Trump said the indefinite extension of the ceasefire

followed a request by Pakistani mediators. However, the U.S.

Navy's blockade of Iranian ports remained in effect, and Iran

seized two ships in the Strait of Hormuz, a vital oil shipping

route.

The bullish sentiment points to a market desperate to cling

to good news, and reflects investor belief that despite

setbacks, the war will be settled at the negotiating table

instead of the battlefield.

"At some stage, this rally is going to come to a halt. But I

don't think that the majority of investors feel that way at

all," said David Morrison, senior market analyst at Trade

Nation.

At 8:31 a.m. ET, Dow E-minis rose 326 points, or

0.66%, S&P 500 E-minis gained 48.25 points, or 0.68%,

and Nasdaq 100 E-minis advanced 229.25 points, or 0.86%.

Risks of an inflation flare-up remain, with oil prices near

the $100-a-barrel mark.

"The peace process is looking wobbly again as some of the

difficult realities of the war come to the fore," said Kyle

Rodda, senior financial market analyst at Capital.com.

"The risk is (that) Iran's domestic political dynamics and

strategic tensions between the U.S. and Iran -- not to mention

Israel -- maintain an inertia towards escalation."

EARNINGS LIFT SENTIMENT

Investors were also scrutinizing a fresh batch of quarterly

reports as the earnings season gathered pace. A strong run of

earnings so far has reassured markets about the health of the

U.S. consumer, the growth engine of the economy.

S&P 500 EPS estimates for 2026 and 2027 have risen by 4%

since late January, according to data from Goldman Sachs.

GE Vernova ( GEV ) advanced 7.5% in premarket trading after

the power equipment maker raised its annual revenue forecast.

Medical device maker Boston Scientific's ( BSX ) shares were up

1.3%.

United Airlines added 1.2% after reporting

first-quarter earnings. Shares of planemaker Boeing ( BA ) rose

3.9% after a smaller-than-expected quarterly loss.

EV giant Tesla, chipmaker Texas Instruments ( TXN )

and Southwest Airlines ( LUV ) will report after markets close.

Adobe was 3.1% higher after it unveiled a share

repurchase program worth up to $25 billion.

Seagate ( STX ) jumped 3.8% after Barclays upgraded the data

storage firm's rating to "overweight".

Crypto-related stocks gained, with Coinbase Global ( COIN )

and Strategy up 4.5% and 6.4%, respectively.

(Reporting by Niket Nishant and Avinash P in Bengaluru; Editing

by Devika Syamnath)