NAPERVILLE, Ill., Sept 25 (Reuters) - Speculators’ optimism across U.S. grain and oilseed futures has returned to late June levels amid increased buying in Chicago-traded corn and soybean products, an uncommon trend leading into U.S. harvest.

This year’s short U.S. corn and soybean crops and the ongoing tensions between Ukraine and Russia have only worsened global grain supply uncertainties, which have been prominent for two years now. But a potential slowdown in the global economy poses threats to speculators’ bullish grain bets.

In the week ended Sept. 20, money managers lifted their net long position in CBOT corn futures and options to 247,909 contracts from 240,643 a week earlier, according to data published Friday by the U.S. Commodity Futures Trading Commission.

That marked funds’ eighth consecutive week of net buying in the yellow grain and produced their most bullish corn stance since June 21. Most-active CBOT corn futures rose 15% in those eight weeks, remaining just under $7 per bushel at their peak.

Corn futures settled at $6.76-3/4 per bushel Friday, easing with broader commodities and equities, though they remain at the second highest levels for the date behind 2012. Subpar global crops have supported corn futures, but demand concerns loom.

The 2022-23 U.S. corn harvest is in the early stages, though sowing has just begun for Argentina. Extreme dryness there has already prompted industry analysts to cut crop forecasts.

Data last week showed U.S. gasoline demand at a 24-year low for the middle week of September, a red flag for corn-based ethanol demand. However, in some countries, high prices for traditional gasoline have spurred demand for cheaper options including ethanol blends.

SOYBEANS AND WHEAT

Most-active CBOT soybean futures were unchanged in the week ended Sept. 20, though money managers trimmed their net long by more than 7,000 to 104,691 futures and options contracts. That is well above the year-ago levels and about average among recent weeks.

Money managers’ bullish CBOT soybean meal views are easily record high for the date, surging by more than 14,000 contracts through Sept. 20 to 102,168 futures and options contracts. That was associated with a 3.7% jump in futures, and it was funds’ biggest meal buying week since November.

December soymeal futures hit a contract high of $443.80 per short ton Thursday but settled lower Friday at $423.30, some 24% stronger than the year-ago price.

CBOT soybean oil futures fell more than 1% through Sept. 20, but money managers added about 3,000 contracts to their net long, which reached 58,310 futures and options contracts. Funds have bought oil in seven of the last eight weeks and meal in seven of the last nine.

But a global economic slowdown could soon hit soybean and other global vegoil prices. An industry leading analyst on Friday said Malaysian palm oil futures could be a third lower by the end of the year based on factors like demand destruction.

A pause in wheat selling since last month has allowed for the increase in collective grain and oilseed optimism. Money managers remain bearish Chicago wheat, though they were net buyers for a fourth straight week through Sept. 20, resulting in a net short of 15,703 futures and options contracts.

Money managers have been bullish Kansas City wheat for more than two years, raising their net long slightly in the latest week to 19,059 futures and options contracts. They flipped back to a net long in Minneapolis wheat for the first time since July with net buying at 2,520 futures and options contracts, the most for any week since April.

Most-active CBOT wheat closed above $9 per bushel on Wednesday and Thursday, the first $9-plus settles since June, as the conflict between major wheat exporters Russia and Ukraine deepened. However, wheat shed more than 3% Friday as U.S. equities and crude oil plunged. Karen Braun is a market analyst for Reuters. Views expressed above are her own.

(Editing by Leslie Adler)