(Reuters) - U.S. stock index futures were mixed on Monday as investors geared up for a week packed with third-quarter earnings reports and economic data that will likely test stretched stock market valuations.

Dow E-minis were down 72 points, or 0.17%, S&P 500 E-minis were up 8.5 points, or 0.15%, and Nasdaq 100 E-minis were up 50.75 points, or 0.25%.

Major financial companies kicked off the third-quarter corporate earnings season on a broadly positive note on Friday, with JPMorgan Chase, Wells Fargo and BlackRock rallying after the results.

Their gains propelled the Dow Jones Industrial Average and the benchmark S&P 500 to record closing highs in the previous session.

Still, with stock valuations stretched - the S&P 500 is trading at 21.7 times forward earnings, versus a long-term average of 15.7 - companies will be forced to justify them and satisfy investors.

"While the bar for earnings overall (is) beating estimates, valuations remain lofty," said Marc Ostwald, chief economist & global strategist at ADM Investor Services International.

There would be "a very big focus" on AI investment and the extent to which companies might delay capital expenditure, among other metrics, due to uncertainty around the outcome of the upcoming U.S. election, Ostwald said.

Forty-one S&P 500 companies are expected to report results this week, including Bank of America, Citigroup, Johnson & Johnson and Netflix.

Year-over-year third-quarter earnings growth for the S&P 500 is estimated at 4.9%, according to LSEG data on Friday.

Investors will also watch for crucial economic data this week, notably September retail sales, which are due on Thursday, for clues on the financial health of U.S. consumers.

Federal Reserve officials Christopher Waller and Neel Kashkari are scheduled to speak through the day.

While traders have dialed back expectations for an outsized 50-basis-point rate cut at the Fed's November meeting after a string of strong labor market data, bets on a 25-basis-point reduction have stayed largely intact at 86.1%, according to the CME Group's FedWatch tool.

Among single movers, planemaker Boeing slipped 2.1% in premarket trading after the company flagged a larger-than-expected Q3 loss on Friday and said it would cut 17,000 jobs and delay first deliveries of its 777X jet by a year.

Investment bank B. Riley Financial leapt 17.5% after the company said it had agreed to sell its unit, Great American Group, to asset management firm Oaktree Capital in a $386-million deal.

U.S.-listed shares of Chinese firms such as Alibaba and PDD Holdings slipped more than 2% each as investors were left guessing on the size of the overall fiscal stimulus China announced on Saturday.

VF Corp fell 3.1% after Wells Fargo downgraded the apparel retailer to "underweight" from "equal weight".

Cryptocurrency-linked stocks such as Coinbase gained 3.9%, Riot Platforms added 3.5% and MicroStrategy was up 4.7%, tracking gains in Bitcoin.