A voice from across the pond helped spark Wednesday's installment of the stock market's pullback.

"We now have a tactical sell signal," wrote Teun Draaisma, chief European equities strategist for Morgan Stanley. World stock markets have marched in unison recently, so the warning from London resonated on Wall Street.

As market gurus go, Draaisma is unknown to most U.S. investors. But his track record and the intensity of his latest warning rang an alarm after it was first reported in the British press Wednesday.

"Our [quantitative] model gave us a signal that has only occurred five times since 1980, always followed by down markets in the next six months," Draaisma said in an e-mail to me. "We advise our clients not to chase this rally, to take profits in any equity overweight they have and to prefer cash over equities. We are overweight cash."

Draaisma's market calls in his current post are few but impressive. Having joined Morgan Stanley in London in 1997, he became chief European equities strategist in March 2006, after his co-head quit to join a hedge fund.

On June 19, 2006, amid widespread stock market pessimism, Draaisma issued a report titled "We Are Buying Equities."

"We think the market reached its bottom for the year last week," he wrote. The judgment was correct. The Dow Jones Stoxx 600 index, a measure of European stocks, and the Standard & Poor's 500 index bottomed for the year on June 13.

In February, Institutional Investor's European edition ranked Draaisma's team second to Citigroup, praising him for "shrewd and accurate predictions."

Draaisma termed his latest signal, dated Friday, "a full-house sell signal."

All three of the principal indicators he tracks -- market fundamentals, equity valuations and risk -- flashed "sell," he said. The final straws were the monthlong increase in bond yields and last week's upbeat report on conditions in the U.S. manufacturing sector, he said.

Since 1980, the triple signal used by Morgan Stanley in Europe has indicated a combined "sell" warning in April 1981, September 1987, February 1990, May 1992 and April 2002. Ensuing market declines averaged 15 percent over six months.

"We prefer to be on the right side of those odds," Draaisma wrote. On the other hand, he maintains a long-term "neutral" rating on stocks.

The Dow Jones Stoxx 600 index dropped 1.6 percent Wednesday, the biggest percentage decline since March 14.

Draaisma said the only piece of his "sell" calculation that remains out of place is investor sentiment.

Based on the behavior of speculators in Nasdaq index futures, investors remain cautious, he said. Normally, a "sell" signal relies on strong investor optimism, he said.

"Arguably, the wall of worry is still being climbed," he wrote.

Draaisma's stock-picking skills might not be as solid as his market-timing ability.

Of two stocks he recommended in his "buy" signal last June, one, STMicroelectronics, failed to perform as well as the benchmark of European stocks. The other, financial service giant Allianz, performed twice as well as the benchmark.

Two stocks he recommended selling, British American Tobacco and supermarket chain Carrefour, outperformed the benchmark.